I had to fly from the bay area to San Diego... and when I went to my company's online travel booking system, one of the options it gave me was SFO-SMF-LAX-SAN, SAN-LAX-LAS-SFO. I figured that if it said it was legal, there was no problem with me taking it!
Interestingly, the cost was only a tiny bit more than the direct flight, probably because I had to make day-before reservations.