At the Olympics if you want to protest a decision, you must have cash:
The reason that Mathieu — and many other coaches across most Olympic sports — make certain they always have a specific amount of cash on hand is that if they want to protest an official decision during competition, they need more than just a strong opinion and an angry yell.
They also need money.
…Depending on the sport, the fee varies: for luge, it is 50 euros (about $67). Cross-country skiing, like snowboard and Alpine skiing, demands 100 Swiss francs (about $112) but stipulates that all protests must be submitted in English. Bobsled and skeleton are among the most expensive: they require a deposit of 100 euros before any protest will even be considered. If multiple countries want to make a similar protest, sharing the tab is allowed.
Hat tip to the excellent PriorProbability who also points out that if your protest is successful you get your money back so these payments are also protest bets.