Once on an AA 757 going from UIO to MIA I was asked to switch my coach E (aisle) seat by/with the lady next to me in the middle seat. (The 3 pax in A-B-C were traveling with the lady in seat F.)
This was before MRTC and I, being 6' 5" tall, declined.
I did offer to switch with the pax in seat C but told her that I simply could not fit in a middle seat. They declined my counter-offer.
C'est la vie.