First year guys get paid second year rates for all open time above their bid line value. Some guys are able to make this work pretty good for themselves. A friend of mine made over $70k his first year by working this angle.

SWA keeps less on reserve than most airlines so you don't have to move up the seniority ladder very far to get off reserve. Right now it's less than 10% of total lines are reserve. Additionally, FO reserve gets used hard so there's very little sitting in a hotel or crash pad waiting for a phone call.