"We left the front door wide open!" was her horrified cry.
Sure enough, the door to our trailer was standing open. I stopped the van and we rushed over, fearing the worst. Amazingly, our home had not been ransacked, and indeed there was no sign that anyone had come in at all. Upon examination, we believe that when Lisa was locking the door, she actually threw the bolt but that the door was just barely ajar when she did so, so the bolt didn't actually go home, but kept the door slightly open. Also, there's a fair chance that the door sat there mostly closed for quite a while, with a gust of wind finally pushing it open.
Looks like we got really lucky.
We unpacked the things we'd fetched from town, and while we were doing so, the person who had blocked the driveway came out and moved his car, so I was able to put my van away where it normally lives while I'm here.
We're a little shaky at the close call. Ironically, one of the things we went to get today was a new door latch for the trailer, and it's the one thing we did not get, because the only replacement door mechanisms at the RV supply store were cheap Chinese junk. The last time we checked, there was still one US manufacturer of those latches, but actually finding one in stock at a parts store is difficult, because apparently the stores assume that their customers only want the cheapest possible junk. And order by mail is sometimes a problem because the vendors online rarely say where the part was built. She'd much rather hold the part in her hand before buying it.