As you can see, in all those well known moves the wheel is pulling the brake out of the frame, and not pushing it into the chainstays.... well done gaps are thought to fall using the wheel the same way (usually we fall in the border). Drops and other moves don't really use the brake too much. I think that if the rider mostly goes up (sidehops to rear wheel, tapping, bunnyhop, etc) he makes his rear wheel to pull the break out. If the rider dedicate his time to make huge gaps and doesn't fall in the border, and making very big drop gaps, he might be pushing the brake into the frame. BY THE WAY, THE PROBLEM ABOUT THE DIFFICULTIES TO SET UP THE BRAKE ARE SOLVED. THANKS