But the M&Ms aren't used in isolation. They're used as a flag, where their presence suggests that the venue did not follow through on their technical demands. Once you know that, then you just look for problems (probably the demands immediately around the M&M line first). Once you found an actual problem, well then, there you go.
They made huge money from the concerts, nevermind the fans. They weren't looking for out-clauses
Nowadays the "big shows" employ teams of dozens of guys travelling and dozens of helpers employed locally, it would be severely negligent if checking of basic requirements would only be done only on the basis if the catering guys met the random demand for colour-sorted sweets.
I organize smaller events, but you wouldn't believe the number of f-ups a bad manager can produce left and right. Often, the "ground crew" isn't even at fault - e.g. I had events where the ground crew was briefed to a standard timetable layout, although we had provided a timetable usable for them beforehand, having them fix a lot of things on the fly.
Before I took a business law class, I figured everything in the contract had to be satisfied exactly. But that's not always how the law works.
I'm talking about U.S. contracts. How would the brown M&M play out in Japan?