I think y'all are giving Red Bull a bit of a hard time about this. It's their trademark, they should be allowed to say what happens with it; that's the point of a trademark.
Aside from that, think about what sorts of things Red Bull does associate with: Extreme Sports and the like; mountain biking, aerobatic teams both RC and full scale, wing suit flying, BMX, etc etc. But they only endorse groups that have proven they can do these very dangerous things safely. Now let's say you throw their paint scheme and logo on some giant FT plane and accidentally crash it into a crowd of bystanders. Their logo was on that plane which makes them look bad even though they didn't put it there. Then someone comes after them for monetary compensation and they have to defend themselves in court. Blah, blah, blah... it's easier to just say no to everyone.