Sounds like a good idea, make it harder for them; down here though, they'll just cut a hole in the trailer.. yep you heard it right, and not just at night in the yard, in the day too when the crews are scattered across a property.
A buddy of mine just had his trailer broken into out in broad daylight. the community security camara showed the men driving up (wearing hoodies... imagine that) put a battery powered saw around the side door and cut the whole thing out. They stole all his reserve handhelds, blowers, chainsaws and hedge trimmers in less than 5 minutes.
We put some screaming sensor alarms in the trailers and mounted faux internet camaras. But if they are motivated, it doesn't matter.
"Those who cannot remember the past are condemned to repeat it".