NLP - my hat goes off to you. I consider myself a "nice guy", but you make me look like Scrooge. If someone asks me to change and I am traveling alone, I will exchange like for like or better. I would not accept a middle seat unless it was an extremely short flight.

When my companion and I have seats that are separated we try to make sure that we are among the first to board. She will go to her seat and I will go to mine. The first prospective seatmate is politely asked if a swap would be possible. Since the assigned passenger has not yet become ensconced and comfortable it is much easier to work a trade that way. I will also offer to vacate overhead space if needed.

If boarding has already occurred and I need to ask for another passenger to change with me, I will offer the better seat that my group possesses as an inducement. (e.g. the seat furthest forward.) I think that it is inappropriate to ask another passenger to accept an inferior seat for my convenience and I will not ask. However, I do hope that when asked politely others would be willing to yield their seat if it is an "even trade".

CWPFLY