The FA SHOULD know. The exit rows are desirable - and only Plat's can get them in advance (except the handicap capable seats) - so FA's should be educated on the advance seating arrangement.

Whenever, someone wants to swap, the FA should always ask that the requesting passenger move to the less desirable seat. FA's should be taught this. (I recently had an experience on an Air Canada flight - needed to move because mother and child were split and one was sitted in an exit row. The FA indicated we had to move you, but to a MORE desirable seat - the exit row).

My experience in F has been that many times when the two passengers traveling together are in window seats - they usually don't ask to swap - since they know the exit row folks either bought the F seat or had a high priority upgrade. They are usually glad they got upgraded and less likely to make a fuss over changing the seat. When they have one aisle and one window - then the swap is easier. The protocol should be that the folks requesting the change be relocated to seats farther back - because of meal choice.