How to know if a contact from Hotmail messenger has blocked me?

I know how to see if someone has deleted me from the contact list, but I do not know how to see if someone has blocked me.
How to know if a contact from Hotmail messenger has blocked me?
Well go into one of them and if it don't pop up then it will tell you if they blocked you and if it pops up then they didn't block you that is how I find out if someone blocks me.
Reply:You can't - they just don't seem to come online anymore....
ghetto names