Yes! That rock band came to my mind, having read about them here at HN. But I couldn't remember the name (Van Halen, see below) or "brown m&m".

Now, because of your reply, I found this old HN post:

"Why Van Halen's tour contract had a "no brown M&M's" clause"

https://news.ycombinator.com/item?id=7754334