I feel your struggle, and I wish you success. But in the meantime, rest assured that OPs issue is fortunately uncommon. You can book two seats in advance and have little or no difficulty. And while OP had some unpleasant interaction with SWA staff, I never have, and I've been booking two seats under the COS policy for well over a decade. It takes a little more patience than booking a single seat, so you have to allow yourself more time at the airport, but sometimes life's a tradeoff.