The blocked recipient does not receive any notification or message indicating that he or she is blocked. I tested it out by blocking my oldest son and then had him send me a test iMessage. Although it showed "delivered" on his iPhone 5, my device was never notified of his message and I never received his message. As soon as I unblocked him and asked that he send me another test message, iMessage worked as it had prior to blocking him.
This for info JMD
This helps.
Good Luck