locking gas cap: yes or no

There have been people on this forum who have vandalized generators so.....

I would say very little chance, someone would have to be really casing your RV to know if you are there or not, and then there is the chance your could come back at any time or be caught by other campers. Most gas is taken at knight, while people are sleeping....they are not going to take it from your RV while you are in it.