I'm confused... what about all of the signs that businesses post up that say "We reserve the right to refuse service to anyone for any reason". Couldn't the Jewish owner post a similar sign, and simply refuse service to the guy while pointing at it?
Should he have the right to post up that sign? That is the question and premise of this thread.
He could also post a sign on his door requiring that all who enter wearing a tie will have it cut off and nailed to the wall before being seated, but that isn't a legally enforcible notice. It only has authority upon those that recongnize that it has any such authority.
And no, I didn't just make that one up. The cut tie scenario actually happened.