(The Feb. 20 story was refiled to make the spelling of guerilla consistent throughout)

A fan wearing Olympic rings glasses watches a hockey game in Pyeongchang. REUTERS/Damir Sagolj

PYEONGCHANG, South Korea (Reuters) - In packing for the Winter Olympics, Canadian entrepreneur Domenico Ciarallo stuffed his bags with hats and t-shirts bearing the logo of his company, which makes locker-room dryers.

Once on the ground, though, he is wary when handing them out to any Olympians even if he sponsors them.

“The athletes put them in their bag right away but they know that they can’t wear these here because you can get caught not wearing official team merchandise,” Ciarallo said.

Ciarallo’s Montreal-based Rocket Sports, whose equipment keeps ice-hockey gear dry, is among a group of companies, big and small, trying to grab attention at the Pyeongchang Games without infringing on official Olympic sponsors.

They also include Apple Inc AAPL.O, camera maker GoPro Inc GPRO.O and Under Armour UAA.N which have been looking for cracks in the IOC's sponsorship wall without ruining the party for Olympic sponsors such as Samsung 005930.KS, Panasonic Corp 6752.T and Nike NIKE.O, which sponsors Team USA.

“Guerilla marketing tactics around large-scale events like the Olympic Games are more comprehensive and complex than ever,” said David Abrutyn, a marketing expert at sports investment firm Bruin Sports Capital.

Sponsorship accounts for a fifth of revenues for the International Olympic Committee (IOC), which protects that income by monitoring closely for any infringements.

“The IOC and its partners in the Olympic movement take the threat of ambush marketing very seriously,” an IOC spokesman said.

But guerilla marketing can still find legitimate opportunities at the Games, though it can involve a lot of legwork and can be toughest for small entrepreneurs like Ciarallo who is advertising his presence at Pyeongchang on his website and by word of mouth but can do little else.

Brewer Red Stripe, controlled by Heineken Holding HEIO.AS, took its golden opportunity when Jamaica's women's bobsled team suddenly parted ways with their coach, who had also been helping to finance their Games campaign.

Red Stripe gave them the funds to carry on, earning global news coverage. But the firm still had to be careful: it created Twitter hashtags #RedstripeToTheRescue and #SleighAllDay which skirted its link to the team and made no reference to the Games.

The Jamaican team confirmed their agreement with Red Stripe. Red Stripe could not be reached for comment.

Under Armour also helped Nigeria’s women bobsledders, outfitting them and making a documentary ahead of Pyeongchang about the first bobsledders to represent an African country.

Online fashion magazine Teen Vogue was among media outlets that posted the Under Armour video during the Olympics, a move the outfitter said brought the “story to consumers that we could never have afforded to market to in the traditional sense”.

‘PLAYING BY THE RULES’

Some big firms, which support individual Olympic athletes or teams without being Games sponsors, can also ask for Olympic waivers which give them approved marketing opportunities on the condition they cannot use Olympic symbols or references.

GoPro, whose cameras are used in extreme sports, secured waivers allowing it to stream video starring Olympians such as U.S. snowboarder Jamie Anderson on social media before the Games. Anderson won the women’s slopestyle gold in Pyeongchang.

At the Games, GoPro also hunted for smaller marketing opportunities. It planned to fit its cameras to non-competing skiers who test the alpine course right before races and to share the footage online, a GoPro executive said in Pyeongchang.

GoPro, which sponsors the U.S. ski and snowboard team, did not respond when asked if this went ahead.

“We try to be very respectful of IOC and USOC (U.S. Olympic Committee) and existing sponsors that we know are paying exorbitant amounts of money to be part of the Olympics,” said GoPro’s global head of marketing, Todd Ballard.

Apple has also found a small opportunity at Pyeongchang.

It lent about 15 gold iPads and more than a dozen Apple watches to the U.S. bobsled team’s coaching and support staff at the Olympics. The coaches had been using outdated iPads to analyze training runs and asked Apple last year for new ones.

“We were surprised when we opened the box from Apple and the iPads were gold. We thought this was a good omen,” said U.S. bobsled and skeleton spokeswoman Amanda Bird.

On the sidelines of the Rio de Janeiro Games in 2016, Apple sold limited edition Apple watchbands in national team colors.

Apple declined to comment.

Ciarallo, the entrepreneur with the upstart dryer company, also knows he must be careful. “I’m playing by the rules. If I do something not so kosher, I’m dead.”