Of all the comments this one is the most reasonable. I do know about the subject ADA law but I don't know who prosecutes when there is a violation or whether the offended person must hire a lawyer to have it prosecuted. Reminds me of something that should be handled in small claims court. Fact is, I don't think he'll ever do it again. Anyway, this is not murder and as has been said in the replies, I think the point has been made.
I only wonder how many other laws we are all ignorant of. There are so many.