If in a questionable area, I lock my Honda 2000s to one of my wheels and around the
axle and the lock in a hard place to reach. While site seeing in Co. there was a young couple told the campers next to us that we had given them permission to "borrow" our gens. Fortunately, we had not left the lock keys with them.
One year in Quartzite, Az., an airstream camped about a hundred yards from us in the boonies, had theirs stolen over night with it sitting out from their camper with an extension cord.