However the Jet Blue flight attended insisted that he has no right to sit in a different seat that was provided to him before boarding, and she insisted that even though its an empty seat, and even though he asked before boarding to change his seat, somehow he is not allowed to seat on the empty seat near his parents,
The attendant was right. You can’t switch to an empty seat during boarding because it can still be assigned to another passenger. I’ve never had any trouble with my seat because I follow three rules:
1. Book early
2. Arrive early
3. Be polite
I don’t always get the best seat but have never been removed from a plane.