Originally Posted by PulledBreaker

That's not the procedure, and he could get left behind because the agent won't be able to do it.

Id90travel.com is how offline jumpseaters list on Frontier. You'll need your login and password. I'd rather you do this early vs standing at the gate watching a single gate agent board a plane without you because they are new and don't know how to list you themselves. Not all are able to.