US Airways Dividend Miles - Booted out of exit row seat?

Just a quick question:

If you book a reservation while being a preferred member and select an exit row seat, will you get kicked out if you lose your preferred status before the flight? Also what about if you select an exit row, but then change your frequent flyer number to a different airline? (Or do both, as will be my case. :p)

Actually, when I put in my United MP number, it let me keep the seat, but if I wanted to change it to a different exit row then it came up with a message saying someone in the reservation must have their Dividend miles number in there with preferred status. Any thoughts?

Different situation, but I as a Preferred have booked a flight, with my PNR linked to a non-Preferred friend and got exit row seats for both of us. I then had to cancel my flight but his seat was not affected.