[f22flyboy]

In defense of suction cups:

Suction cups that mechanically create a vacuum are actually pretty good at handling lateral force. They are the kind that are used for moving large panes of glass. One suction cup independently definitely won't stop 130lbs at 10 fps, but multiple ones, well placed, and backed up with good drive system, can probably stop all but the most powerful (and determined) bot.

edit- the way we tested this - a 160 student did pullups hanging on to 2 suction cups attached to a vertical pane of glass. Probably not the smartest thing, but it proves that they will hold lateral force. Also, multiple suction cups spaced out will minimize the chance that a large scratch will mess them up.