My brother-in-law had his Quad stolen in January. When the policeman came to see them (two days later - but that's another story) he actually told my B-I-L that if it happens again in future and he catches them, his best bet is to attack them and beat them up - the chances are the police will never catch them and if they do, they chance of them being convicted is incredibly low so you may as well try and deter them yourself.
That was a policeman's serious advice. And would my B-I-L now be in court if he'd done that? More than likely!