Although they can be pricey there are RV security systems on the market that provide alerts to you cell phone in the event of an intrusion. One such system is:
The RV Security System. Cellular Video Security on the Road or in Storage.
I can see where these type systems would be beneficial to full timers or folks that park the RV at a campground on a seasonal or long term basis. Also for those that place their RV in a relatively unsecure (no 24 hour security) storage facility for the winter.