I made it home almost every weekend during systems training. Our FSI guy had us "start early" on Friday and "work through lunch" so that we could leave around 2-3pm to make flights home. If SWA serves the city you are trying to get to outta STL, you're made in the shade. If there are more than enough seats in the cabin, they won't even check CASS. If they do and you come back denied, they will barely even flinch and give you a seat in the cabin if one is available. I tried using American while in training ONCE and while I made it on, it was a huge headache as the gate agent had no idea what to do with someone who was CASS denied and did not possess American benefits. The gate agent WAS extremely helpful though and eventually "worked something out" and told us to get on and keep our mouths shut.