I had an AA pilot do this for me years ago...and I'm United! He listed and got called for a seat in the cabin on the last flight home out of ORD. So I'm rolling through the jetbridge door last minute with the CSR... and the glares I got from the AA FA who was now staying the night in the terminal!! I thought she was gonna whoop my arse.
I have never forgotten. I always do what I can. Whether it's giving up the JS for a seat in the cabin or yes...MY SEAT IN THE CABIN FOR A JS! :0 It can be done in a way that doesn't hose a junior pilot. Most CSR's will agree to wait until last minute to make sure nobody needs the JS. If not. Fine. Just give me the cabin seat and screw our fellow employee.