Forgetting the rules of war and all that for a minute, I always thought the perfect weapon for stopping non-compliant vessels was to give them a quick zap w/ our laser on our FLIR, since I can't shoot them or throw things at them. Worst case, they'd get burned and be annoyed, which might distract them from doing what they're doing. Best case, they'd be blinded and bumble around at the helm until they stop. Either way, I'm sure it wouldn't tickle.