This was at the gate, 15 minutes after scheduled boarding time. That is why I was persistent - because obviously the flight was already closed, everyone who was checked-in was already at the gate (or should have been), and I could see that there were only a few dozen people at the gate, not three hundred. It was only because the load was so obviously light that I did not accept the initial response that business class was full.

So, to review, GA told me business class was full. I asked her to check. She checked her terminal and repeated that it was full. As I posted, we went back and forth on this a couple of times, and then the team lead said: "Sir you are right. Actually business class is not full on this flight."

If GA had said "Sorry, I don't know if there are any seats available", I would have found that very weird, and I'm not sure how I would have responded. But I would not have posted here about being untruthful. But that's not what happened. The agent checked her terminal, and then gave me, repeatedly, factually incorrect information. I know it was factually incorrect, because eventually her supervisor told me so. Hence my post.