First, if an airport pusher is pushing you, they will take you to the front of the line. If you're doing it yourself, someone will probably direct you to the front.
Second, if you are using an airport chair, whether they take it for a while, or leave it with you, depends on whether you are able to get up out of the chair or not. Since, I can't, the chair stays with me. If you need it to, for example, get to the restroom during the time waiting for next fight, then you could sit your ground and keep it with you until boarding.