Van Halen had one of the most oddly specific requests of tour riders: a bowl of M&M's, with all the brown ones removed was to be placed in the dressing room of every venue on their 1982 tour. For years, it was seen as complete folly — the band was making a ridiculous demand of concert organizers simply because they could get away with it.
But the seemingly ludicrous request was actually a shrewd business move. (I was reminded of it while reading Ian Parker's excellent profile of New York Times food critic Pete Wells in the New Yorker; he mentions the Van Halen M&M episode in passing.)
The band's concert rider indeed had a clause saying there could be no brown M&Ms in the backstage area, or the promoter would forfeit the entire show at full price.
As lead singer David Lee Roth explained in a 2012 interview, the bowl of M&Ms was an indicator of whether the concert promoter had actually read the band's complicated contract.
Diamond Dave explains more in his biography - "Van Halen was the first band to take huge productions into tertiary, third-level markets. We’d pull up with nine eighteen-wheeler trucks, full of gear, where the standard was three trucks, max. And there were many, many technical errors — whether it was the girders couldn’t support the weight, or the flooring would sink in, or the doors weren’t big enough to move the gear through.
The contract rider read like a version of the Chinese Yellow Pages because there was so much equipment, and so many human beings to make it function. So just as a little test, in the technical aspect of the rider, it would say “Article 148: There will be fifteen amperage voltage sockets at twenty-foot spaces, evenly, providing nineteen amperes …” This kind of thing. And article number 126, in the middle of nowhere, was: “There will be no brown M&M’s in the backstage area, upon pain of forfeiture of the show, with full compensation.”
So, when I would walk backstage, if I saw a brown M&M in that bowl … well, line-check the entire production. Guaranteed you’re going to arrive at a technical error. They didn’t read the contract. Guaranteed you’d run into a problem. Sometimes it would threaten to just destroy the whole show. Something like, literally, life-threatening."
And here endeth the lesson on the importance of contracts, by Van Halen.