Think from a home security point of view, if you leave your keys by the door someone could just use a hook to get them. If you leave them at the top of the stairs on a hook, anyone coming upstais for the keys will see them first and hopefully just take the car, leaving the occupants alone. If they come into the bedroom anyway, its survival of the fittest. Another problem with fending them off is reprisals, as they know where you live. Shouldn't put people off defending their property but something that needs bearing in mind first.