Use common sense and take reasonable precautions. We don't stay in rest stops or truck stops. Too noisy and just not for us. We have stayed in Walmarts, Cabelas, Sam's Club, Lowes and Home Depot. We always ask beforehand (except Cabelas which usually have RV spots). If we are not comfortable with the location we move on.
We have two dogs who bark if they hear or see someone around the coach. I lock my outside compartments and can activate an audible alarm from my coach key fob. We may leave our docking lights on if it is otherwise dark where we are. When I take the dogs out before going to bed, DW watches us from inside the coach with the door locked. We have small arms in the coach if anyone should try to break in while we are there.
Been traveling around the US since 2004 and never had an issue. Not saying it can't happen but I think you can reduce the possibilities by being aware of your surroundings and taking reasonable precautions.