Surely commonsense should be the buzz word. We have all been in places where we felt uneasy, maybe without real cause, but in those circumstances I tend to move on.
However, I am not going to spend my whole life worrying about whether leaving a caravan or car for a short time is going to result in theft. Yes, they are important to me and yes, they cost money, but that is as far as it goes. Taking that sort of stress a bit further and one will be wondering if it is safe to leave your van in a site while you are away touring. And before anyone states I am being nonsensicle, think about it. If someone drove up to a van along the way and proceeded to hitch it up, do you think anyone would really ask why the number plate was different?? They would all assume it was a friend or relative. If you knew the people in the outfit personally, then maybe, but do you?? And I am sorry, but wardens do not check who is leaving the site.
Again sorry, but life is too short. My van is a bit of aluminium and wood and it is insured. It is also protected by a Theftbeaters system. In addition I keep nothing of serious value in it so if someone really wants to knick it, then so be it.