Was this at SFO terminal 3 or in the International terminal? I believe the GS check-in area is in terminal 3, which would make for a very long walk if you were in International terminal.
I am more amused than surprised by such bickering. A thread like this one has made me more aware at all the nonsense ant entitled behavior happening around airports. It would have been amazing to witness if these two folks were to be seatmates on their upcoming flights.