On our return trip from a week + in the ShowLow AZ. area we stopped at a Mickey D's in Williams, AZ. I was sitting in the truck with the hounds and DW was getting some vittles. There was a gas station/tire shop across the street and a fellow walked over towards the truck and said, you are about to lose the spare tire off your FW, pull it over to the shop and we can look at it.
Sure enough it had backed off about 2 inches. I always check wheel torque, tire pressure tighten screws for cabinets and drawers but I never thought about the spare.
I slipped the gentlemen a 10 spot which he said was NOT necessary, but considering the consequences, was a cheap fix.
I saw a spare come off the back of a Jeep last year. It rolled down the road, hit a riding mower that was parked in a lot with a for sale sign on it then proceedd to smash in the door of what looked like a nearly new Dodge pickup. I was next door getting a tire reair on teh MH. The guy in the tire place said it happens a lot --- glad the guy spotted it for you and you had it taken care of before a real problem resulted.