Not many people know that rocker David Lee Roth from Van Halen had a famous "brown M&Ms clause in all their contracts. It stated that they wanted their venues to provide M&Ms backstage but no BROWN M&Ms.
Was Roth a diva? Not quite. Roth did this so he could easily tell if the venue had read their contract! If the M&M clause had been provided, it was likely the other requirements in the contract had been as well. He felt that this helped them put on a safe and successful show. If the venue hadn't removed all brown M&Ms he ordered every item in the contract checked for that venue's production. The rumored $85,000 costs in damages to an arena floor when a venue had not provided the brown M&Ms? David quips "Who am I to get in the way of a good rumor?"
The lesson for you is make sure you read through all your vendor contracts from beginning to end. Unusual small items may be hidden and buried deep in your contract, and you don't want any unpleasant surprises on your wedding day!
Image via The Smoking Gun, additional information via Christopher Cummings and Wikipedia.