How was the teacher to know that it didn't occur during school hours? If he read in the paper, I imagine it didn't tell exactly what time it happened...it may have just said that the figure skater was signing autographs monday afternoon. If the OP had just taken the time to say something the first time he made mention of it, he would have been aware of what you are saying...that it happened after school hours.
The OP didn't have to come up with a witty comeback or an on-the-spot excuse when he mentioned it, just the truth would have been enough to clear up any misunderstandings. I am still not sure why she didn't. To be honest, her lack of response when he said something in front of her (repeatedly) does nothing but suggest that she felt there was something to hide.
I have to say, I have had 3 children in school for over 13 years and I really do not understand this 'us vs them' mentality when it comes to the people who are teaching our children. I can't even think of more than one or 2 situations, in all of the years, where I had even a minor issue with my childrens teachers. But I know many, many parents who are constantly criticizing their childrens teachers over every little issue. Even here on the DIS, on any given day you can find a thread where a parent is taking issue with something their childs teacher did or said. Some justified and some just petty nitpicking, IMHO.
Sheesh, they cannot win....
We don't want them to think they are God, but we expect them to be perfect.