Pack light or stow it. It's not all that hard. They also fly out of less expensive airports, so their operations cost less. I love the low-fare lines, and wish SW had a powerful ally. And you land right downtown, in an old, underused airport.
People still do it, and it's a neat way to get around the airlines' restrictions.
Travel agents can be penalized for issuing these tickets, and some have been. But if you buy the tickets yourself, in two separate transactions, I don't think you can get caught. I'm not sure what the penalties are if you get caught, or whether anyone caught has ever taken this to court. A strong argument can be made that, once you purchase a ticket, you can do anything you want with it, including not using it. The airline won't penalize you if you simply don't use a ticket you buy, for instance.