Originally posted by NoelMc:[..]
That's not exactly how's it's told in the book! Bono did not go looking for an illegal substances but did admit that he could have ended up in a lot of trouble!
Other than that, I'm not that sure about cocaine being a common feature in their backstage, I don't really care, but I don't remember anything to support that, other than guessing based on the expectations of a successful rock band.
On the other hand it wouldn't surprise me about the weed, and alcohol has always been a well known fact.