Mud can transfer in the opposite direction, too. The Houston Astros paid $2 million to erase the Enron Field name off its baseball stadium.

Poorly behaved athletes and teams are just one way sports sponsorships can go awry. Companies looking to attach their names to an event, says McLaughlin of Deloitte Consulting, need to be concerned about everything, from security to adequate seating to unruly fans. "There could be bad news around the event for whatever reason," he says. "It's kind of unpredictable."

Which is one reason why Toyota gets involved in the nitty-gritty of all racing events that bear its name, including the 30-year-old Toyota Grand Prix in Long Beach, California. On average, Unger says, the company will begin planning - with the event promoters, Toyota's advertising agency, and corporate staff, as well as dealers in the area where the event is held - about five months in advance. The dealers, because they know the local market best, decide which vehicles and products go on display; ad buys and promotions are planned; guest lists are assembled. It's a big commitment, and not just in terms of the dollars required to secure sponsorship rights. "Forget dollars. Time is critical because you only have a finite number of hours in the week, and we need to be able to plan these events in a way Toyota is comfortable with," Unger says. "We don't just write a check and say, 'Put the signs up, put the ads up, and blast away.' "

While it is a strong supporter of sports sponsorships, even Toyota admits that measuring an event's effectiveness is difficult. From its area dealers, Toyota gets a good sense of an event's effect on immediate sales. The company also simply looks at how many people showed up, or "butts in the seats," as Unger puts it. Beyond that, "it's not as scientific as you might think," he says.