Dogpilot....as to fuel thieves, you're talking airplanes that have a lockable door, of course.....

Mine don't lock, and even if they did, all you'd have to do is rock the wings a bit to pop a door open.
I agree on following the manufacturer's recommendations....to a point. For example, consider Piper's recommendation in their checklist for the Piper Warrior III in engine starting: Turn master on, mixture full rich, turn beacon on, turn ignition switch to "start". Crank for ten seconds, if engine has not started, PRIME the engine 2 seconds, then re-engage the starter.
Whoever in Piper ever thought up that checklist apparently hasn't ever actually started one of these things. My point is, manufacturer's checklists are not necessarily sacrosanct, and most of the manufacturers of GA airplanes will tell you that. GENERALLY speaking, they provide good recommendations. I always try to understand WHY they recommend something, and as you say, there are often VERY good reasons to follow their guidance.
You need to train those locals better. I parked airplanes on the ramps of some not so friendly ALaska villages, and I know of only one case where someone screwed with an airplane. And, in that case, the VPSO brought the perpetrators to me within an hour. I'm sure it's happened more times than that, but up there, everything these folks consume comes via the airplane. Messing with airplanes is a quick way to "interrupt" your air service. No booze or cigarettes for a month changes behavior significantly. Other parts of the world, maybe not.
MTV