I saw the email too, but it said "our Gold customers". Now maybe it is anyone in the seat, and maybe it covers ALL events of seat swappage, but I am not so sure... or at least that email sure isn't clear.
Aircraft Swap Seat Protection
Exit rows are part of our preferred seating program and many of our Gold customers prefer these seats for the extra legroom. However, during equipment swaps of same aircraft types with disparate exit row configurations (900s / 800s), passengers preassigned to exit rows can be unseated and moved to other seats in the replacement aircraft as defined by our reservation systems reseating logic. A flaw was discovered in this logic last year, where customers preassigned to exit rows were reseated in the very back of the replacement aircraft. We've corrected this flaw, so that our Gold customers are reseated in the new exit row or as close as possible to their original preassigned seat location.
Project Owner, Allen Weymiller, Central Reservations
Also, the last two times it happened, I put him in the reclining seat (based on AS seat map) and he ended up in the non-reclining seat on both 5/1 and 5/14.