Mostly I just sit on the sidelines, eat my popcorn and enjoy the games here, but every once in a while I throw the popcorn bag at the computer and start typing.

The things that seem to be working like a burr under your collective saddles are (1) F/Os 'checking' captains, (2) F/Os flying in the left seat and (3) the fantasy argument that if F/O Flexes fly occasionally in the left seat, this somehow causes you to get excessed. Let's get edumicated here:

(1) F/O PCAs are allowed under the contract. Under the AQP, the only 'check ride' is the LOE and that requires an APD which requires a line holding captain. Any other F/O PCA event is Train to Proficiency which means as long as you satisfactorily complete all the objectives in the allotted time, you pass. All of these events are MANEUVERS oriented. Seems a good F/O flex can train/validate a MANUEVER as well as any captain to me.

(2) The F/O flying in the left seat is type rated and perfectly legal to do so under the FARs. Under our contract, the F/O flex is REQUIRED to be checked out as a captain. If they fly in the left seat, they are required to fly with a SCA/LCA in the right seat, so it's a double bump. You must not like getting paid to sit at home.

(3) I won't even address this. If you think that the very occasional left seat trip for a F/O flex has anything to do with captains being excessed, I'll just encourage you to get back on your meds. Fast...

Just because someone is a captain doesn't mean they don't suck and just because someone is a F/O doesn't mean they do. You should focus on the quality of your instruction instead of the seniority of your instruction.