There are numerous pilots who left AAI (with several years of longevity) to start off at the bottom at SWA over the past ten years. That's because they desired a SWA pilot's career well more than maintaining their seniority at AAI. Those pilots will be directly affected if they're slotted below the pilots who were below them at AAI.

Other pilots at SWA made similar decisions to come to SWA over other places--myself included. I know I valued a job at SWA well more than a job at AAI (as well as two majors I was hired at) ten years ago and still do today. Hence, I'd be dismayed to see someone who took a job with AAI 10 years ago be slotted ahead of me on a combined list.

It's too bad that we can't go back a year and ask people what position they'd be willing to take on the opposite list. I'd guess SWA pilots would have required a huge jump in seniority to take a job at AAI (and any SWA CA and most senior FOs would've turned down the transfer for any jump). I'd also surmise that most AAI pilots would've been willing to take a big loss in seniority to transfer to the SWA list.

Alas, we can't do that now. Still, anyone who thinks that relative seniority is reasonable seems irrational to me. It comes off as someone who wants to keep their cake and get to eat it too.