I've been asked to move on a number of occasions. Never once been offered any compensation. My bet is the pax who wanted to move were cash F pax.
Last time I swapped in F was earlier this year. I was aasigned 2K, and a family had 1A, 1D, 1C and 2D. I happily switched. 2A was unoccupied and I basically ended up with two seats, while the family got the entire 1-2DK zone.
I think it's common for folks not to realize there is a wall between A and D.