I'm a F/O with PDT and was nonrevving DAB-CLT on an extremely full mainline flight recently.
While I was at the gate podium, gate agents discussed among themselves about how I wasnt allowed to ride in the cockpit. They KNEW mainline pilots can ride in the cockpit on Express flights, or wait...maybe its the other way around? No no no Express pilots can ride in the cockpit on mainline flights but not the other way around!
I just shook my head and said no, I'm not sure where you guys got that from, but we're all in CASS so it doesnt matter.
"Hmm...are you sure???"
"Yes I am".
I pointed out theres a list of dozens and dozens of airlines on the PDT website OPEC might be referring to, and they would be surprised at the number of airlines pilots can jumpseat on.
Sometimes all it takes is a little polite insistence or just request they talk to the captain if they are unsure.
Well, since you're a PDT pilot, you don't need to be run through cass to ride any US Express or mainline jumpseat. The only time that applies is when you're riding an offline jumpseat. Offline jumpseat here means Delta, American, United, etc. If you're riding anything with USAirways / USAirways Express on the side, no need for cass verification. Most gate agents don't seem to know that.