I had the pleasure of experience blacklisting from Triton. Of course it was a misunderstanding, but shutting down our server without notice was a huge loss of confidence, we lost many users. It was hurtful for our 500+ users and for me personally.
If a server got blacklisted and the blacklist is removed, the client still refuses the connection. After 1-2 attempts the client will connect again. (server beta28, client beta31)