you were on their page? :T
Answer on If you press FOLLOW by accident on Twitter, and then immediately click UNFOLLOW and block them? will they know?
nahh they wont know. and when you block them, they won't be able to follow you.
Yeah, if they do get email notifications. I personally turn mine off so maybe the person did, too. But if you block them, they won't be able to follow you. But they will still be able to go to your profile if they know your twitter name. and you won't know that they see it. your best bet would be to block the person and protect your tweets.