(2) Civil liability does require, generally, causation--cause-in-fact and proximate cause. The cause-in-fact test is a simple "but-for" assessment: but-for our guy disabling the wireless, would the robbery have happened? In this case, yes, in the absence of our guy disabling the wireless, the bad guy would have still robbed the house. Disabling the wireless did not cause the robbery, the criminal was acting independent and without knowledge of the wireless camera's being disabled. Proximate cause is a more complicated legal standard, but since cause-in-fact is missing here, our guy isn't liable, and your second point is probably incorrect.