I don't worry about it. Thefts are very rare in campgrounds, otherwise tenters would never leave their tents unlocked. Personally I think that if you feel unsafe enough to replace door locks, then you should find another place to stay.
AFATG if someone really wants into your camper there is nothing you can do to stop them, the door jambs are all aluminum. A large screwdriver and they're in, while doing major damage to your trailer.
Seems to me that most thefts happen while the trailer is in storage, not the campground.