@Thomas,
Yes, there are people who would lie to avoid embarrassment. Didn't get a joke. How humiliating.
I don't happen to be one of those people. Foist of all, not getting a joke is nothing to be embarrassed about as far as I'm concerned.
Second, lying about it is something this kid wouldn't do. Fact is, lying is something I very rarely do.
I thought the two of you knew me. I guess not that well. Sigh.