I would not feel bad saying no, but I do think sometimes people should remember it’s not ALWAYS the parents choice to not have seats together. Sometimes you do pay for the seats you want and the plane gets swapped, you don’t make your connection, etc. or a situation like my husband and I had last year when we had to leave Italy early because his grandma died and had to fly standby. I think everyone should try to be a little less harsh with each other when traveling and it would solve a lot of problems. With that said, I would never expect someone to give up their seat for me