Originally Posted by
dilanesp
At some point, if you run a business and people are gaming your system, you have to make decisions that might make things a bit harder for non-gamers to stop the gaming.
How the heck are two people choosing the seats they want to occupy "gaming the system"? In most cases, they don't want to sit in the middle seat either. They paid for their tickets and they did so before your hypothetical late traveler. The fact one of them may be willing to move to the middle if someone shows up for the third seat is courtesy, not theft.
There is no obligation for people who are married, related, or just traveling together to sit next to each other. In point of fact, I see enough of my family that I usually don't feel a need to sit next to them on the plane.