Interesting stuff, although I must admit that when I asked - for some reason I was thinking along the lines of: fork truck enters box - LG not down, fork truck and big truck fall down, although that doesn't seem very likely.
That walk around would have caught a left open roll up door I will admit to forgetting on a couple of occasions - Most have probably done that at one time or another. This was when I got a bit lax about locking said door with the lock left in the location you mentioned. With the truck backed up to my bedroom window at night and being nearly always near by during the day............easy to get lazy and I am lucky nothing fell out. Though the truck was empty both times, the pallet jack has one of those Pallet Truck Stop...Cherry's 800 350-0011 under it (which everyone should have) there was a box near the door I keep a shrink wrapper and infrequently used straps, tape, etc but it stayed put for the 10ish miles down the interstate.
Then one day heading into Canada I got asked if I had looked in back, was it locked? - of course I had a PP excuse for both which was followed by a final question. "How do you know someone didn't put something in there?" Point taken, door is now locked at all times, even driving from one side of the street to the other - the side benefit to that is the door never gets left open since a key is needed to lock it and with the cab locked - I can't get in without retrieving the key from the lock.
On your tire incident.........that's another case were a GPS will help you, in most cases it will located nearby businesses, at least tomtom's will.
Thanks for the tip on the Pallet Truck Stop. I had never seen this device before. If I ever make it back on the road I will definitely invest in one of those. Sure beats load locking the thing in everytime.