Is this really possible?

[Rubi]

Don't worry dear,
if you blocked to anyone then you never get any information from that person.
There is no way to do like this.
So just keep enjoy.

[Angeleyes]

When you block someone they cannot see anything about you and same if someone blocks you.

[Myname]

If they block you, they will not see your posts and activity from their account, but they can always make ANOTHER account and spy on you from that.