What was wrong with Bill Bennett's release system.... He had the right idea of not letting go of the control frame while doing surface launches... it appears that this system would let you escape a lockout fast without moving your hands form the uprights or bass bar.
What I do see, it may make steering the glider a little harder and not having too much pitch control while on tow and maybe that is why pilots decided to tow under the bass bar and not from the front of the glider, this unit is almost the same system for aero towing, except it goes to the front of the bass bar and not to the keel... if it could be re-modified, somehow to work for platform towing that maybe the trick, keeping the main release on the bass bar and somehow modifying it to go under the bass bar on to the pilot. I have read of pilots crashing because, they were hanging on for dear life and did not reach-out to the main release for whatever reason they experienced during their last moments
http://www.youtube.com/watch?v=8b82susQK5Y