When I had my TT, it was broken into in a "Secure" storage facility. They couldn't bust the locks on my storage doors so they pried them until the could just basically bust the doors off. To get the main door open they busted out the window. Worst part of it all is I had taken everything out so they didn't get anything. The damage on mine, and several other trailers resulted in them getting almost nothing.
Unfortunately, RV's aren't particularly strongly built. My own experience is that better locks won't do any real good when the doors are so easy to warp and thus break open.