To continue the drift -
I fully support Nutloose's action to prevent petty pilfering in his business/hangar and his fears about the poor lad's Screwdriver. We all have our favourite worries and his is FOD, it seems.
In support of his control fears and most others' fears of civil maintenance practices - I would like to explain that, while it may seem 'a bit unsafe' not having tool controls "like the military do", the emphasis we civvies have is to make sure the aircraft is FOD-free at the end of any work - rather than just accounting for tools used within the local environment.
The dangerous bit is allowing FOD (of any sort) to stay on the aircraft - and that is not really prevented by building complicated methods of checking tools.
NL has stated the best tool control system - your willingness to buy expensive replacements!