Laughed myself silly on this one! First, I don't think I ever saw the words "leaving tea" used together like that before, and secondly it reminded me of that detective game, "...it was Mr Longgone, in the library with the poison [tea]..."
Have a great leaving do, I've had a few and at least one stands out in my memory as both fun and surprisingly thoughtful, may this one do the same for you :-)