Does someone know if you block them on Twitter?

[Randomness.]

Someone recently started to follow me on twitter but I don't want that person to be updated with my tweets.

If I block them, will they know that I have blocked them? Or will they just not get any more of my tweets?

Also, my tweets weren't protected before but now they are.

Thanks in advance!

[Kelsey]

They will only know that you blocked them if they were to hit the "follow" button on your profile; it would say something like "blocked", but they wouldn't be able to contact you to complain anyways.

Since you locked your tweets, they shouldn't see them at all.