Originally Posted by
Jersdawg
It is highly recommended you don't do that, but if you do, make 100% certain there are no commuting pilots you will bump. If there are, the jumpseat belongs to the CA and it is his right to kick you off to allow a commuter to get on. Then you'll have a mess on your hands trying to get your cabin seat back, and the flight very well may leave without you. Don't let an agent talk you into taking the jump on any A pass, either.
^^ This. Plus also tip for new guys, if your deadheading home from a sequence or training on an A3 make sure you check in 24 hours before hand and get your seat assignment. If you turn up at the gate with an A3 and the flight is full then you’re screwed.