After going to meets where guys are flying 3D, I've gotta say that its all about communication, and common courtesy. If your up with 1 or 2 guys, and they don't mind you hovering, flipping around down low (out of there way), its not a big deal. I'd only feel comfortable if I knew the other pilots and discussed it with them prior to flying in that manner.

At events, to really do some 3D stuff, you'd have to be up by yourself, or fly up higher or lower to stay out of the way of the others.

Whenever there's 3+ people flying, forget it, it's not worth it (doing 3D).

As for the midair at superman, I was calling for the Maverick pilot, and by the time I finished saying "watch out", they hit. The closure rate is unreal with the jets.