Toilet Paper on My Shoe

Dear Law School Ethicist:

There is a guy at my law school I don't speak to because, among other things, he makes fun of Harvard people and I am a Harvard man and proud of it. When we cross paths, he says "hello" or some inane thing like "why not speak to me." I just stare into space and completely ignore him.  The other day as we crossed paths he said, "There is toilet paper stuck to your shoe." I again ignored him and went to class where I discovered there was toilet paper stuck to my shoe -- about 7 feet of it. It would have been embarrassing but being from Harvard I know not to blush.  Here's the problem, if something like this happens again -- he tells me there is bird poop on my shoulder or that my zipper is down -- and I check have I, by acknowledging him, broken my resolve to ignore him. Can I ignore him and act on what he says at the same time?

Thanks, Chadworth Hunnington III