What about some video security?
Some years ago I was looking at a potential hangar, and one of the things we were going to do was automatically triggered video recording from inside the hangar, streamed over wifi, with a 3G fallback (it was a remotely located site).
That would also take care of cases of "hangar rash" to which nobody owned up That happens fairly often, especially if there is a syndicated aircraft in there, with say 10 members, each of whom has a key.
Nowadays, these systems are not at all expensive.
And you need internet (with wifi ideally) for preflight activities.