For the avoidance of doubt, in that situation I agree that one shouldn't lie. I was commenting not on B's behaviour and attitude but on A's.

And, also for the avoidance of doubt, if Chris's girlfriend was upset that he told her the truth rather than that he didn't like her friends' acting then she was being 100% unreasonable. (And, as I said, even if it was the latter, still pretty unreasonable. I was making a more general point.)