Though the stealing of RV's is not as common as the swiping of cars. It does happen from time to time, we hear about one or two on the forums every year..
USUALLY however they take motor homes, or they take a trailer WITH TOW VEHICLE attached.. Why do they not take the trailer.
Well there are some very good trailer locks out there, If I wanted to swipe your trailer they would not even slow me down, Not at all.. But I'm not in that business and ... Well.... I do have something the average vehicle thief lacks (I will let you figure out what it is).
A good hitch lock might slow me down.. But the average thief is defeated by even the simple ones.
When I towed trailers.. I used a padlock to "Pin" the hitch (It is recommended you pin it so it does not accidently become unlatched) and that's all it takes to stop many thieves. They cant hook up with the lock there.