Benefit concerts are great. The practice of bands playing to raise money for a cause can be as local as helping a fellow unsigned musician pay for their son's hospital bills to as international as world hunger. Though we may pinch our noses at the perceived sanctimoniousness of people like Bono and Bob Geldof, we have to admit that their hearts are in the right place. They're trying to help; it's just that their method involves getting a lot of personal attention.
Poster for the No Pain for Zain Benefit
The thing about charity concerts is that, well, they still involve regular people and the music industry. No matter what you do, the same leeches, incompetents, criminals and other peripheral folks that make being a rocker a trap-filled traitorfest are still going to be involved because you still have to find a venue, sell tickets, record and market the event, and whatnot.
That's where the process breaks down, and even musicians with the purest of intentions find their attempt to make the world a slightly better place has now been undeniably pissed in. More often than not, it doesn't actually wreck the endeavor, but if you're out there planning on tackling an issue with a concert, then maybe you should read about the pitfalls.