Originally Posted by justhere

The logic is that the pricing is based on the demand and market forces, etc. Most airlines don't allow hidden city ticketing however Southwest has in the past specifically allowed it and at the very least doesn't seem to prohibit it currently. Not sure if you can short check a bag but if you only have carry on you can just get off at BWI and tell them you aren't flying on the 2nd leg.

Just be aware that I don't think you will earn any points for either leg if you do this. Also, this is one of the many reasons to buy one way tickets on WN instead of round trip. You don't want your return canceled because you skipped a leg of the trip.