Hmm, do most people run their clients with an explicit "-rescan"? Or do you mean that he suppressed its default behavior? I just run it in whatever defaults it has.
As for restarting, I don't leave my main PC on 24/7, so it starts (and stops) at least once a day, usually.
I
did recently update the client to the latest version (within that two weeks - A few days ago, Sunday or Monday I think), but it seems strange it would have taken a few days to "heal" my local blockchain if something had gone wrong. Usually those sort of things work as an all-or-nothing proposition, it either works or fails.
Weird, anyway.
Incredibly glad it resolved itself (hey, I use BTC(etc) mostly for fun, but can't sneeze at almost USD$200), but still somewhat creeped out by the sudden coincidental fix.