Willie Sutton was once asked why he robbed banks. His response was "Because that's where the money is". Crime and problems are more prevalent where there is more opportunity. That usually means a higher concentration of people and assets in close proximity (easy access, easy get-away, etc). When you're out camping, or even just RVing around, you tend to be among like-minded people with a much lower potential level of crime.
I grew up in the boonies in Alaska. We never locked the front door - not sure we ever knew where the key was. There never were strangers, just people we hadn't met yet. I find that RVing is a lot like this which is one of the things I really enjoy about the lifestyle.
But don't use this as a replacement for good old common sense. Be aware of your surroundings, your neighbors and don't do things that make you an easy target. People in general are honest and trustworthy, but temptation can be overpowering in anyone.