Contracts
Bikers have been known to be a lot of things, but businessmen are not one of them. That is more of just a recent trend that has been growing among groups like the Hells Angels. But from time to time they have been known to do deals with celebrities for events and other things.
The famous rock and roll band known as The Rolling Stones signed a deal with the local Hells Angels in one of the areas they were having a concert in. The deal was to pay the gang money and in exchange, they would provide security for the concert. The concert ended in a riot, so we guess they were not good at it.