Hello,
Checking prices for a trip via UAL , SFO-PVG:
Booking SFO-PVG-SFO the price is $1245
Booking exact same day and same SFO-PVG-SFO flight
LAS-SFO-PVG-SFO-LAX-LAS the price is $921
+$324 for flying directly out of SFO

A) Are there any negative consequences of not using the return SFO-LAX-LAS portion of the ticket after clearing Customs/INS with my baggage? I know I am required to present my baggage to UAL just outside of the Customs hall for connecting flights.

B) If for some reason my baggage was mis-routed and arrived at LAS rather than SFO and I stayed in SFO, what consequences if any might occur with UAL?

I suspect getting my baggage back to SFO and clearing Customs might present a problem..
Thanks