OK, so locking pin it is...any idea on how to service it? I'm really comfortable under the hood, but interior and body just aren't my thing..
For the "moving forward" question, it was most definitely #1, sliding as though it were spring loaded. I am 100% positive it did this. I even had it reaffirmed by some co-workers I was driving to lunch who commented on how the seat used to be able to do this and now it can't, without me bringing it up. I was also able to confirm the feature on a friend's 330 of the same year which also has electric seats.
To add to the accident comment, since the seatbelts and their tensioners are built into the seat on the vert, you essentially get trapped in the broke seat if the locking pin were to break...