Would you please elaborate about seats at the gate? Is this a matter of opening up seats that were blocked during OLCI? Because otherwise I would imagine the better seats would already have been assigned by that point. But maybe I’m missing something.
If you've been allocated a duff seat you've been unable to change online or at check-in, gate agents have been known to help. It's not an enshrined benefit, not something you should feel entitled to, just a little kindness that's occasionally brightened my day.
Clearly only unassigned or unclaimed seats come into play.