Although Nike invites its devotees to "Just do it", the sportswear giant wouldn't have expected Wayne Rooney, its brand ambassador, to follow its advice to the letter with a hooker calling herself "Juicy Jeni".
But, according to press reports, he did. And the England striker must now wait to see how much he has damaged his value as an advertising property by "playing away".
It certainly poses a dilemma for Nike, as well as Rooney's other sponsors, Coca-Cola and the computer games manufacturer EA Sports. All of them must weigh up the inevitable outcry about Rooney's morality with the potential damage their brands might suffer were they to be seen as "fair weather friends" ready to abandon their big name at the first sign of trouble.
"Advertisers who use celebrities have to recognise that it's a partnership," Robert Campbell, the Beta founder, says. "They have to be there for the 'lows', as well as the 'highs'."
The official line from Nike, Coca-Cola and EA Sports is that the matter is a private one for Rooney and his family. This is true - but only to an extent.
"As a sponsor, your first job when a scandal breaks is to find out what actually happened so that you can be sure of your ground," a commentator who has studied the relationship between the ad industry and celebrities points out.
"You have to be certain that what happened wasn't illegal. If it was, then it's vital you drop your celebrity quickly. At a time when corporate responsibility is so important, you can't afford to do otherwise."
Churchill, the car insurer, was one major advertiser to do this when it ended a five-year relationship with Vic Reeves after he had pleaded guilty to a drink-drive charge. In doing so, Churchill followed the policy of most advertisers in backing their celebrity spokespeople as long as they stay on the right side of the law.
Santander takes a similar approach, and maintained its support for Lewis Hamilton when he was disqualified from the Australian Grand Prix for "misleading" stewards during an inquiry into the latter stages of the race. "An indiscretion is one thing," Keith Moor, Santander's director of brand and communication, says. "Doing something illegal is quite another."
Few expect Rooney to have done irreparable harm to his sponsorship prospects. David Beckham's red card in the 1998 World Cup game against Argentina - and the subsequent story of an affair with Rebecca Loos - proved no turn-off for sponsors.
What's more, nobody believes the dip in Tiger Woods' advertising fortunes in the wake of his admitted infidelities will be anything more than temporary.
Indeed, there's a view that Rooney's reputation will actually enhance his value for certain brands.
Hamish Pringle, the IPA director-general and author of the book Celebrity Sells, says: "Being a bad boy is much more in line with Rooney's nature."
In fact, the only thing that may dent Rooney's earnings isn't his alleged philandering but what is a growing reluctance among advertisers to use famous faces.
Morrisons, the supermarket chain, is one, having recently shelved its celebrity-led campaign in favour of using "real people".
George Prest, the executive creative director of Delaney Lund Knox Warren, Morrisons' agency, warns of the perpetual danger of celebrities becoming the brand. But he also suggests other factors have come into play.
"It's partly linked to the recession," he says. "Using celebrities in your ads marks you out as a big spender. And with increasing newspaper intrusion into the lives of celebrities, it's becoming harder than ever to find one who doesn't have a skeleton in their closet."
CREATIVE - Robert Campbell, founder, Beta
"The private lives of celebrities who appear in ads do matter because clients, in general, are conservative. But the fact is that celebrities can turbo-charge your message - and they're much less risky than a meerkat!
"A good example was our use of Jamie and Louise Redknapp for the Thomas Cook campaign. I was instinctively against the idea because the casting was odd but it actually worked very well.
"If a scandal occurs involving a celebrity, the sponsoring brand needs to roll with the punches. Sometimes a situation can be turned to an advantage. I would have loved Virgin Atlantic to have signed up Naomi Campbell after she got banned from flying with British Airways."
PR - Ross Cathcart, senior director, Ogilvy PR
"If Rooney apologises with genuine humility, people's natural instinct will be to forgive him. But it does emphasise how important the celebrity selection process is. Whoever is chosen affects your brand values so it's vital you pick somebody who shares them.
"But if your celebrity does transgress, it's important that the subsequent advertising credits your audience with some intelligence. The smart move would be to adopt a 'we know that you know' approach.
"And while real people have featured in highly successful campaigns such as Dove, sales of magazines such as OK! and Hello! suggest there'll always be a demand for celebrities in ads."
CLIENT - Keith Moor, director of brand and communication, Santander
"Signing a celebrity is always a risk and advertisers have to accept that. It also means choosing that celebrity is a serious decision and you have to be very clear about how you plan to use that person.
"And that decision isn't entirely to do with consumers. We also have 20,000 employees. Being associated with F1 via Lewis Hamilton makes them feel proud that we're such a big player.
"However, it's vital that you keep your celebrity association under constant review. We track our association with Hamilton monthly. There's a constant trade-off between what you buy when you sign a celebrity and the return on that investment."
INDUSTRY BODY - Hamish Pringle, directorgeneral, IPA; author, Celebrity Sells
"It would help Rooney were he to own up quickly to what he allegedly did, apologise for it and, if necessary, say he's going to see a sex counsellor.
"Sometimes, though, notoriety can actually extend your appeal. Look what happened to Kate Moss, who was dropped by H&M after drug allegations but went on to have a successful association with Top Shop. However, had she been prosecuted, it would have been a different story.
"And nobody should consider doing anything like the ill-conceived and embarrassing Tiger Woods comeback commercial for Nike, which reflected very badly on his advisors."
- Got a view? E-mail us at firstname.lastname@example.org