I'm not one, but know some guys who do it. Lots of RJ's. Certain times of the year their is one mainline flight so not many jumpseats to book. Most guys use Frontier over Delta RJ's. Southwest has some flights, but not as many as they used to. Any city where the RJ's are mostly SkyWest is a pain because you can't list for a jumpseat and a ramper's mother who was hired yesterday will be ahead of you on the non-rev list.