Originally Posted by Adlerdriver

Bzzzzzt! HUGE foul.

Your airline contract may vary, but there a so many reasons why this is a bad idea. Just a few:

1. You have a contractual right to a positive space seat for company directed DH. Enough people settle for a JS and now you're having to justify why you need it when it's time to negotiate your next contract.

2. You end up screwing a commuter out of the JS. You don't know how many people the gate agent turns away after you take it or you're already down in the cockpit.

3. You take it, give up your seat to a revenue passenger, they board the jet and a last minute pilot senior to you bumps you off the JS. You think the gate agent is going to kick the pax out of your seat without a fight? Maybe you get to talk to a CP about why you didn't get where the company wanted you IAW your pairing. At the very least you've got one POed pax if you do get your seat back. Or maybe you end up sitting around the terminal waiting on the next flight to your destination.

This was probably the second thing everyone was taught about jumpseating (behind asking the Captain for the privilege and saying "thank you" when you block in).