1. When paying full-fare, flights are fully refundable. Not sure when you are flying home? Just book a bunch of flights. Even with the restricted fares, you get 100% back in SWA credit which can be used for the same person for one year. I'm surprised they don't have a 24 hour cancellation policy as I'm sure they lose money when flight sell-out and last-minute, full fare passengers book on other airlines. Even a $20 fee would provide incentive to cancel redundant flights.
2. Frequent flier points can be used to book restricted fares as effectively fully refundable -- if you cancel, you get the points back. So, just book-up a bunch of segments before prices go up in case you need them. There might be a $2.50 (yes, under three dollars) fee associated, but it's immaterial.
3. If you "miss" your flight and get to the airport within two hours of its scheduled departure, you can fly standby on the next one. There's an incentive to book a mid-afternoon flight (usually less expensive than, say, a 6:00 PM one), "miss" that flight, and standby on the more expensive one.
All-in-all, I don't abuse the rules much. Mostly, the lack of any fees for missing my Monday morning flights makes me less interested in showing up at the airport too early. I'm simply surprised that SWA doesn't provide me with small incentives to change my behaviors in ways which would help them immensely. Conversely, their website seems to have a bunch of O(N) or worse algorithms w.r.t. number of trips taken -- a huge annoyance to their most valuable customers.