Found myself today repeating the “brown M&Ms” story about Van Halen and thought to check its veracity. This article persuades me that it was less quality control, more image management.
In the late 1990s, though, the story shifted as additional context emerged. David Lee Roth, the band’s lead singer in those early years, published a 1997 autobiography titled Crazy From the Heat, in which he claimed the bowl of curated candy had an entirely functional purpose: It was a quick way to see if the venue had actually read the whole contract, line by line.
Source: Why Did Van Halen Demand Concert Venues Remove Brown M&M’s From the Menu? | Arts & Culture | Smithsonian Magazine