I'm going to build on your idea. For the sake of spreading knowledge I will say that a normal laser pointer likely won't disrupt or damage a quality digital camera. A class IIIb laser, like a rave laser, or a powerful IR laser shined at the camera for an extended time would permanently damage the sensor of most digital cameras.Maybe set up a laser pointer right into the camera lens.
I don't condone destroying someone else's camera, but a class IIIb laser mounted to a tripod pointed at the sensor and lens would probably do the trick.