TAMPA — Four middle-aged men breeze out of the Marriott Waterside Hotel into an already hot morning, looking like business travelers about to take in the sights.

One glances at a map. Another takes a swig of water. Mostly they try to act like everything's normal, even if it isn't.

These fellas are being surveilled, part of a two-day security course for executives who travel to hot spots overseas. Their test is to figure out who's watching without being obvious about it.

Maybe it's the 20-something woman toting a dachshund in a small carrier, the athletic-looking guy sauntering by on the opposite sidewalk, or the white-haired executive in the pin-stripped suit.

They make it to their first planned stop, the Unlock Tampa Bay visitors center at the foot of the PNC Bank tower. It's not open yet. The door is locked.

"What now?" says a former CIA officer who is shepherding the group and providing tips along the way.

The men know it's a good excuse to pretend to figure out what to do next.

"That's right. It's a legitimate reason to stand here for a minute," says the CIA man. "If someone is following, they might come around the corner and run right into you. That's a good way to spot a tail."

They eventually walk on toward their next destination, heads on a swivel.

A GROWING THREAT: Corporate debt hits all-time highs. Could it trigger the next recession?

• • •

The mock surveillance run is part of a two-day workshop put on by Anvil Group, a multi-national security firm. The idea is to teach the 13 men and one woman how to be safer, smarter and more aware when they go overseas.

Several of the participants come from the country's largest and best-known companies. They sell machinery and weapons in tenuous locations. One travels on behalf of a cigar company. Another works in tourism. They swap stories about the way governments and competitors have tried to steal their trade secrets, including blackmailing their executives and engineers.

For security reasons, the Tampa Bay Times agreed not to name the companies or the former CIA officer.

The classroom component, held in a bright conference room in Anvil's downtown Tampa office, includes a stream of practical advice.

Cover the camera on your laptop computer to thwart electronic spying. When you're in a hotel room, shove a $1 rubber doorstop into the crack around the door, an effective tool for foiling hotel room invasions.

Flick on the TV and put out the Do Not Disturb sign before leaving your room, which can make would-be thieves think someone is inside. For added security, leave on the bathroom light and close the bathroom door. A thief who gets in might assume someone is in the bathroom and flee.

Know how you will get from the airport to your hotel. In some countries, it's a good idea never to get in a car unless the ride was prearranged.

"We aren't trying to give anyone false comfort or present that they are suddenly going to be Jason Bourne when they come out of this course," says Brad Pupello, Anvil's director of strategic operations, who served as a counterintelligence specialist in the Marine Corps. "We are trying to ensure that our clients are less likely to become victims."

• • •

The training escalates to basic self defense, how to dress a wound and what to expect in the aftermath of a terrorist bombing.

The former CIA officer, who leads several of the classroom sessions, sports a gray suit, no tie and functional black shoes. With thinning salt and pepper hair, he'd look at home at a life insurance convention.

Blending in is one of his talents. Anvil's bio says he spent "35 years in complex global operations," also known as spying in dangerous places. Part of his job was keeping weapons of mass destruction out of the wrong hands. Despite his serious CV — or maybe because of it — he laces his lessons with funny anecdotes and dark humor.

He explains who's most likely to kidnap travelers in various countries. Criminals in Mexico looking for a quick payday. Terrorists in Iran who want to make headlines. Armed political factions in some sub-Saharan countries. Unauthorized taxi drivers in Turkey who will force their victims to withdraw money from an ATM before letting them go.

The participants practice breaking free from duct tape wrapped around their wrists. Same thing with plastic zip ties. One way includes reaching your wrists to your shoes and rubbing the ties across your laces. Done right, the heat melts the plastic.

"But what then?" asks the former spy. Escape can be an option, but it requires a plan, he says. He relays that in his 35 years in the business, he was never taught how to break out of restraints, though he was trained on how to survive in a small box for hours.

Always think several steps ahead, he emphasizes repeatedly.

"If you break free from terrorists, but have nowhere to run, they will catch you right outside the building where you are being held," he explains. "At that point, there's a good chance they will beat you to death."

The CIA man goes on to talk about what to do when the rescue forces arrive, and the shooting starts. Lie face down on the floor and don't move until one of the good guys finds you, he advises.

"The guys coming to get you will be amped, switched on," he says. "Jumping up and yelling 'I'm here' could get you shot."

Most of the group nods. One man chuckles nervously.

• • •

Some sort of surveillance precedes many crimes against business travelers overseas, whether it be a pickpocket watching to see where you keep your wallet or a kidnapper trying to figure out your routine. That's why the training includes how to spot a tail.

In the classroom, the group learns how to use staircases as natural places to look behind yourself, and how to funnel followers into a single line, like through a tight walkway or across a narrow bridge where followers are easier to detect. They're told that crossing a road before turning left or right provides a longer sight line for a quick glance back.

Watch for people or things that appear out of place. The former CIA officer explains how he and his colleagues knew which car some Eastern bloc spies were watching them from by the mound of cigarette butts piled up outside the driver's side door.

IS YOUR JOB SAFE? Artificial intelligence will change the way we work.

• • •

Back on the street, the former spy explains to the four men that he did surveillance runs like this in cities all around the world. The idea is to pick three or four places that a business traveler would typically visit — convenience store, hotel, tourist site, shopping district. They should be at least 20 minutes apart and require changing directions. The time and distance makes it easier to make multiple sightings.

A woman stops behind us as we cross East Kennedy Boulevard into Lykes Gaslight Square Park. She wears flip flops with bedazzled toe pieces and carries a dark backpack. A few minutes later she follows us into the CVS drug store and walks out without paying for anything.

Maybe she's just another ghost, the name given to all the people you start to think are following you but aren't? But she might be the real thing. How do you determine the difference?

"You have to be willing to live with some uncertainty," the spy tells me as we walk the route. "If you're 80 percent sure, act on it."

That could mean retreating to the hotel and informing the company's security team. In most cases, confronting the person or playing games is a bad idea. That can make the traveler more of a target. Besides, savvy travelers know they are being followed without letting on that they know.

"It's about having a high degree of situational awareness," says the CIA officer. "The goal is to get the bad guys to say, 'Hmm, he's making it hard for me to surveil him. Let's move onto another target.' "

After a planned stop at the Starbucks inside the Hilton Tampa Downtown, a burly man with a beard and sunglasses appears to glance at the group and then crosses the road. Probably a ghost.

Later, a woman in beige shorts slips in behind the four men on the Riverwalk. Could the smart phone strapped to her arm be recording what they say? She ambles along for several hundred yards, powers past and then slows down again. Suspicious.

Ten minutes later, the four men huddle with another group of participants in the Marriott lobby. Pupello and the CIA officer explain what they did right — using sight lines, not looking too obvious, taking a photo along the Riverwalk that might capture someone lurking in the background. There were a few stumbles. One man left his map, with all the pre-planned stops, on the checkout counter at the CVS.

A moment later, five strangers join the huddle, the fake spies — three men and two women. The woman with the flashy flip flops and the burly guy with the beard are there. But the woman with the smartphone and beige shorts? She was a ghost.

Only a couple of the participants saw any of them more than once. Many didn't see them at all.

RELATED: More business news

Contact Graham Brink at gbrink@tampabay.com. Follow @GrahamBrink.