@Aquataris: I wasn't sure I understood the problem as you described it, so I investigated the thread myself to see what I could find.
I found two problems. The first is that people cannot leave the roleplay without being punished via blacklist. That's not letting them leave peacefully. You really should not ever try to prevent someone from leaving a roleplay via threat of punishment. Blacklisting as a concept should be reserved for outstanding circumstances, such as trolls, griefers, and outstanding rule breakers in general. I mean, to be honest our roleplaying community here is far too tame for there to be a need for blacklisting at all.
The second problem is that when they left, you sort of bunnied their characters a bit and it upset them. That's an issue of respect. While you had the authority to do what you did, it wasn't very respectful and that's what upset them.
In this case, the alternative way to handle it was by retconning the immediate event and moving on as if it never happened.
Retcon is slang for Retroactive Continuity and is a term that basically means that something is erased from the script, so to speak. It was roleplayed out yes, but then you go back and say it didn't actually happen. Because the character in question was being waited upon in a battle it would've been proper to simply say the battle did not happen and have the characters move on as if that character had silently managed to leave while they weren't paying attention. (Alternatively, you can have the characters just not remember him/her at all, but this can cause awkwardness.)
What I would recommend? I would recommend removing the blacklist altogether and issuing a brief apology to the roleplayer in question. The problem should be solved.
@Diamond1304: Oh hey. You reminded me to put the guide through spellcheck. I completely forgot. |D All those instance of a character missing here or there were a result of me working on the guide on my phone whilst out of the house. |D Touch-screen keyboards aren't that great, and all. A couple of those corrects you gave are actually... off though. It looks like an error I'd expect from a false positive spellchecker. I might actually recommend that you download "After the Deadline", a Chrome/Firefox addon that serve as a very powerful spellchecker that integrates with your browser. (It adds a small icon to the lower right of post boxes that you can click to check the spelling, grammar, and even writing quality of a post.)
Anyway, I have now run the guide through a moderately intensive spellcheck and also simplified a couple of words/phrasings down where convenient.