did you happen to check All the UA LAX-SFO flights yesterday and know for a fact that when the OP asked about a F seat on another flight that in fact there were empty F seats?!

No way today can you know what was the story yesterday when the OP asked, even if a flight shows today that there were empty F seats that doesnt mean it was avaialble when the OP asked

Im no lover of Jeff but I really wish that people would use their heads before simply posting another person jeffed up, since they make themselves out to be worse then jeff himself