The company I used to work for did something similar where they sealed the cabinets with the same sort of plastic lock found on hospital crash carts. The problem, though, was that the vehicle service techs were unreliable at best. After a few times of finding things like an open OB kit or an adult BVM with pediatric mask, I stopped trusting the seals to ensure that everything was there. While no patient care was harmed by the lapses, there's a big difference between hospital work and prehospital work. If something is missing in the hospital, there's a central supply area, pharmacy, and other floors where equipment can be obtained quickly if need be. If my BVM is missing from the sealed and checked cabinet, then I don't have a BVM and I lack the ability to rapidly quickly acquire one.