Maybe, but probably not. CASS is worthless without a reciprocal agreement.
Not true. Look in your FOM. Usually, most are worded that a cockpit jumpseater is allowed with the absolute minimum qualifications of CASS approved and PIC approval. Reciprocal agreements are union led, and to be honest, a bunch of BS. I remeber while I was at Pinnacle a CA that I was flying with denied a CASS-approved pilot because that pilot was not in our list of approved recip jumpseat list. I wanted to get him on, and told the CA that as long as you approve of him, and since he is CASS approved, we can take him. CA asked if that was written somewhere, so I showed him in the FOM. It was the bottom of the classification list, after secret service, other company pilots, other DCI pilots, etc, it was Class 8 in the FOM. He still ended up leaving that guy behind. That jumpseater was shocked, he said he had never any issues before and had taken Northwest, Delta, and Pinnacle before.
Oh well... some people just like to flex muscles or prove a point. One time at my regional, I even had a pilot deny a GoJet pilot a jumpseater. It never ceases to amaze me the pi$$ing matches people are willing to get into to prove some point, at the expense of someone trying to get home or to work. Of course I only saw this at the regional level. At my airline, I've taken no less than a dozen GoJet pilots from ORD to both SFO and LAX, and every time our Captains take them on with a smile and a welcome aboard!
Of course, now that GoJets is a DCI carrier, I don't think they'll be getting denied as much. What goes around, comes around. Today you deny a GoJet pilot the jumpseat, tomorrow, he's operating a GoJets aircraft from ORD to your home city and guess what>>???