There's a story about a bowl of M&M's that made up a famous rock act's rider it was a heuristic to determine the fitness of the venue if they couldn't get a bow

There's a story about a bowl of M&M's that made up a famous rock act's rider it was a heuristic to determine the fitness of the venue if they couldn't get a bowl of brown M&M's ready how could they be trusted with the safety of an entire soundstage?