So, what's the deal with this alleged perk? On my recent SCL - MIA - DEN - COS, I ended up with seat 27A on the first leg (767), 19B on the second (757) and 13A on the last (727). My reservations for this flight were made at least three weeks ago.

These would not seem to be choice seats, especially the middle one on the 757. It's not a matter of late check in, as I did that 12 hours in advance (of the MIA - DEN leg). I thought seat allocation was dictated by Mileage Plus level.

Is this something that's happened to others?