Removing a Contact
Removing a contact will notify him that he is no longer authorized to view your presence. If he ignores the notification, you will remain in his roster and you will always appear to be offline to him.
Zoe decides to remove the contact Tex Bingles from her roster. She right-clicks on the contact and selects remove.
She confirms that she wants to remove the contact.
Meanwhile, Tex receives a notification saying that Zoe has removed his authorization. This means he will no longer receive presence notifications from Zoe. He can do nothing about it if he chooses, but the logical thing to do is to remove the contact from his roster. If he removes Zoe from his roster, he will stop sending her updates on his presence, which as of now will be ignored anyway.
Tex right-clicks the contact for Zoe in his roster and removes it.
He confirms the removal.
Just because a contact has been removed does not mean that he cannot send messages to you. To ensure that he cannot send you messages, you can add him to your privacy list.