When my key was stuck in there, I do not believe the steering wheel lock was engaged. The issue of pulling that steering wheel back (in response to another post) is pretty obvious I think for most people with these cars because there seem to be times with most cars I've owned that if the lock is set, you have to pull the wheel back a bit to get the key out of there.

Steve mentioned something about the plate being loose. Is this something you can tell just by sitting in the car, or do you have to remove the tumbler to tell? My feeling on this is that if I'm going to get that tumbler out of there, I'm going to go ahead and replace it anyway for the $60 bucks for a new one. But if there were a way to diagnose externally of course I'd do that first. The gist from your post and others is that it's guesswork in the end (?)

That being the case, proactive changing of this thing sounds like a good idea. My car has 125,000 miles on it. It was the first time it ever did that to me (lockup like that) and it was scary. I was reasonable sure there for a bit that we were absolutely stuck wherever we were.