The elderly Jeep had, shortly before we went on the trip, developed a problem with the ignition lock: it would sometimes stick in the RUN position, and refuse to turn off without some aggressive jiggling.
I'd spritzed some cleaner / dry lube into the lock, and jiggled it further, and it hadn't exhibited the problem again, but we'd intended to take the thing to a repair shop, post-trip, and get the lock cylinder replaced, 'cause it seemed like there was a jamming-prone tumbler, possibly owing to brass shavings (considering how much brass had gotten shaved off the key over the years).
Well, before we got around to that, it did it again. I guess that was last Thursday. Joy drove it home, and I disconnected the battery and hit the starter to kill the engine, then left it sitting there in RUN with the battery disconnected. Friday, I had the dreadfuls. Over the weekend, I tried poking at the lock in various ways, but this time it was jammed quite solidly.
So, today was time to deal with it: make sure the usual repair shop was prepared to replace a jammed lock cylinder, and then either call for a tow or reconnect the battery, quick-like hit the starter, drive the thing to the shop, then disconnect the battery again....
Or, happy thought: call a locksmith. They make house calls, don't they? Googling around turned up one that claimed to do automotive locks, though what they announced on their web site was automotive door locks. Still, worth a call. Yeah, they can replace ignition lock cylinders. Took a few hours to get someone out here (I had said it wasn't urgent). Aaaaand... seems the normal removal procedure doesn't work if the lock is jammed (this is consistent with household locks, now that I think about it). And the procedure for getting at the lock cylinder on an old Jeep is painful at the best of times. So, he had to go fetch the special tools, and come back, and work until well after dark, but he did eventually get the cylinder swapped out and the steering column reassembled.
Got expensive, but I suppose it would have gotten expensive at the regular repair shop too. And now the old scow should be good for another... well, until something else breaks or wears out, anyway.