New Orleans Saints quarterback Drew Brees felt the heat when he tipped $3 on a $74 Chinese restaurant bill. In light of his five-year, $100 million deal, there's only one conclusion: What a cheap $%@!

Not so fast. It was takeout.

In the world of restaurant transactions, we know two things: We don't tip at McDonald's, and we tip 15 to 20 percent at a white-tablecloth, fine-dining restaurant. It's everything in between where things get murky.

Harry Balzer, who researches food trends for the national NPD Group, says takeout is a driving force in the industry but that 90 percent of all takeout meals come from fast-food restaurants, meaning takeout from a full-service restaurant is much less common.

About the Brees flap, he said, "The way to look at this is: Do you ever tip anywhere for a meal you pick up? It's one thing if they're delivering and another if you pick up."

So that sounds as if $3 isn't so bad.

Doug Coe, bar manager at Bern's Steak House in Tampa, sees things differently. Although Bern's does minimal takeout, he tended bar at 220 East on Davis Islands for eight years, overseeing all takeout orders. He says restaurant workers know that the tips for takeout will be all over the map, but they expect about 10 percent, which means Brees was $4.40 shy. But Coe wasn't quick to condemn.

"If he were an average Joe, people wouldn't be mad, but they know how much he makes and expect more. I've waited on high-profile sports people around town, and they generally tip, usually about 20 percent, even on takeout. I saw Charles Barkley on Oprah say that he tips everyone $100, even if you park his car."

Jane Yan works behind the counter at China King in St. Petersburg, where the lion's share of business is delivery, with some takeout. She says takeout customers tend to leave a couple of dollars, which goes directly to the person behind the counter. But in general, counter employees are making more than the Florida minimum wage for tipped employees, which is $4.65 per hour.

On a busy night, an Outback Steakhouse may have four take-away servers on duty. They take orders, double-check the food and pack it up, making sure condiments, napkins and silverware are included, and whisk it out to the car. Yes, each transaction requires much less time than the 90 minutes or so of tending a sit-down table, but these runners earn the Florida minimum wage for tipped employees and thus depend on tips. Even if tips average 10 percent, take-away servers may pocket between $50 and $100 a shift in tips.

Lisa Jennings, an editor at Nation's Restaurant News, writes regularly about tipping issues. She said things have gotten increasingly muddy with non-minimum-wage workers.

"The gray area is the quick-service (Starbucks) and fast-casual (Chipotle) concepts, which now almost universally put out tip jars," Jennings said. "These are segments within the restaurant industry that were supposed to be tipping-free zones, but now tip jars are everywhere."

A recent BBC story explaining the nuances of American tipping to a British audience gave these guidelines: 15 to 20 percent for a sit-down meal, 10 percent for a buffet, 10 to 15 percent for delivery. It said nothing about takeout.

In this wide swath of gray area, consumers are sometimes motivated by shame — but servers beware. Last week a food truck employee in New York City was fired for complaining on his personal Twitter account about a customer who racked up a $170 bill and didn't tip.

Perhaps with takeout, the best guide is your conscience. If someone works hard on your behalf to put together your order, tip accordingly.

"Some of my greatest relationships have been with people I've met through restaurants, people I've taken care of and who have taken care of me," said Coe. "Tipping is good karma."

Laura Reiley can be reached at lreiley@tampabay.com or (727) 892-2293. Follow her on Twitter @lreiley.