I noticed something kind of similar to this last Sunday flying JFK-MSP in the evening. We were about 2 hours late leaving due to ATC delays and my wife & I boarded and sat in 3 A&B. There were 2 seats left in FC and 2 people got on, the lady had 4D and the guy some seat back in coach. She made the comment that they were not sitting together and he took his seat in the back. A minute later she motions him up and asks the guy in 4C if he would move to 3D so she could sit with her companion. He did. She then made the comment to her companion that they were in FC and seemed quite giddy about it so I figured an OP UP since it was oversold in coach. About that time the guy in 4A gets up and goes to the FC restroom right when the last PAX boards and I hear the GA tell her to take any seat in FC as she was an Elite. She goes to 4A and the guy in 4B says 4A is in the rest room. She says she was told to take a FC seat but goes to coach. I thought about speaking up about the couple in 4 C&D but said nothing as the GA had already shut the door. I have not seen something like this for awhile and would have pressed the issue if I had been the lady told to sit in FC.