I've had 2 different in-line protectors now. No problem with theft. If you have an extension cord, you can always plug the extension cord at the post, run it under the camper and then plug in the protector. At the other end of the protector, plug in the camper. You can kind of hide the protector this way. I did this with my first protector. It made me feel good and no fear of theft. The second one ... I simply plug in at the electric post now.
Here's a photo. I've posted this before. See if you can tell where the protector is?
Can't find it?

Look a little closer:
