Never a problem boondocking or in parks...having said that use caution and common sense when boondocking...if it looks bad it probably is..one time we stopped we had passed a rest area that had several campers in it and we opted to go to the next area...well the one we stopped at turned out to be miles from anything we were the only camper there..had no cell service...but we had no problems but that was the one time we thought we might....
Keep your door locked don't open it to anybody....stay where others stay..truck stops are normally better than rest stops...as far as off the grid boondocking the same thing applies if you are the only person there you might be a bit more at risk than it there are other rvers around......remember tho you are never really sure who the guy next door is...