For Apple to reject him and even withdraw AC+, this guy (OP) tried to fix it himself or was curious about the internals. He screwed with AW physically...and i don't mean water damage from showering. I am sure Apple has ways to look for tampering. OP did tampering and Apple rejected him.
We all know that Apple takes care of its customers for the most part...for Apple to do this, there is clear evidence of tampering. IF OP takes legal actions, i am sure that he will lose quickly because the tech will show documents showing that he tampered with the watch against warranty policy.