I have seem some washers with small spikes on them to help protect against twisting. I think my rig uses those.
As for cam locks, I have been thinking of replacing the cam locks on the storage bays with
these. Namely the 8mm triangle drive or the double-bitted one. It looks simple enough that would-be thieves don't think there is some cool stuff the lock is protecting... but it is rare enough that someone having a "
key" just to fit it isn't going to happen pretty much.
Of course, if the doors were not made out of the flimsy plastic/foam that is typical, I'd upgrade to
Abloy cam locks that are excellent when it comes to dealing with foul weather.