Originally Posted by
flyerCO
Thus no method for you to reserve one.
FWIW I once sent a Twitter DM to request one when I wasn't even traveling -- it was for mom and 2 friends who had a connection from something like F to A/B. Twitter said they'd make a note but no guarantees, although Mom said there was a cart waiting when they deplaned. Still could have been a coincidence though, they do seem relatively frequent.
So it can't hurt to ask.