never really gave this much thought...but the rider back rest has a quick detachable device and I suppose someone could walk away with one quicker than **** goes through a goose. I guess I'll be locking mine in the bags from now on when I walk away from the bike. I know it's not fool proof but out of sight out of mind.

 

I am trying to solve this conundrum myself. Anyone know of any solutions? I've thought of an expanding screw/bolt/screw combination, but have not tried it yet. It would not be a lock per se, but would certainly slow em down and that is usually all it takes.