msn的說明
●The blocked contact does not know he or she has been blocked. You simply appear to be offline to them.

●Deleting a blocked person from your contact list does not remove the block.

●A person you have blocked cannot contact you directly; however, you might find yourself in a conversation with the blocked person if you are both invited to the conversation by someone else.

由此看來，應該無法直接看出自己是否被封鎖。用第三點的方法，請第三者邀請你跟懷疑有封鎖你的人一起交談，應該就可以查出來了。