IMO, if a would be thief or burglar were to enter my home,from the second they make the conscious decision to trespass onto my property uninvited and enter the building, or any other part of the premises, they are fair game.
Somewhere, i have one of these...
It's not sharpened or anything, as it has been decomissioned or made safe, however you say it, but if i were a burglar and met a home owner that was holding something which looked like that in their hand, then i would probably make my way out pretty darned quick!
Not that i could hold it tho, because due to my moving house twice in as many years, i cant find it, i know its here at my parents somewhere, but i just cant pinpoint where!