All camper trailer owners need to get a bit more creative in the proactive area of making your camper harder to be shifted quietly, by low life scum. i know there are electronic movement allarms, that you could probably find mentioned on here, via search,, but nearly everyone has forgotton the old mechanical version of these devises is within your hands.
Hang cow bells under your trailer,, make long strings of old enamel plates, old cooking pots, billy cans, like you would see on the back of a car tarted up for the bride and groom to leave in after the reception,,lol,, attach them to the underside/rear/back end of your trailer, just after it gets dark. If your camper is close to, but not behind a/your front fence,,run lengths of fishing line towards your house, with said noisy implements attached to them.
Don,t forget to remove them when you are leaving.
Anything to make a lot of noise so a mongrol grub can,t be quiet as he goes about his neferous activities. Its a first defence and a harmless booby trap,, for the criminal boobs.