When I had my bikes, I had one of these (http://www.allcocksoutdoorstore.co.uk/store/product/8134/Alarm-Gun-to-Fire-12-gauge-Alarm-Blanks/) across the garage doorway at ankle height.
Not best pleased to be disturbed in the night but none of my stuff ever got stolen and you'd hear it go off so could ring the police.
I have no qualms in dealing with stealing scumbags! ;D
I have put a double electric fence around the horse which has detered some idiot that was going in with him, the first fence on the ouside is very visible and signed all along but the second fence is wire and not visible in dull light. I heard a scream from the top field the other night but by the time I got there they were gone and the horse was still in the field looking horrified. These people aren't there to steal him but they give him food which makes him not want the food I give him and is making him loose weight so it is for the health of my horse who really could do without a bucket of apples a day.