Rouge has this problem with the 321s in two different configurations where they end up switching the fins last minute and end up screwing up who has the exit row or not. This is a fairly big deal since the exit rows on those planes are the best seats in economy by a very significant margin, and there is nothing like boarding and finding out you are not sitting where you expected to - this has happened to me more than once flying to Vegas or Florida.
That being said when I've ended up in this situation I've just sat where my BP said to sit...