Just a thought (and I know I could quickly test this myself, but I'm at work and while I've not seen it in my work's AUP, I'm fairly sure I would get in trouble for playing Minecraft here), but what happens if you access a server that doesn't have a mod running that you have installed client side? Eg. if I connect to a server without BC, but I have BC installed. Does the server reject the connection or does it allow connection, but you just can't use the mod?
The reason I ask is that if we get this Ultimate Modpack that I've heard mentioned on here as a future possibility, then surely we could create our servers with whatever mods we want enabled/disabled, then someone would just need to use the Ultimate Modpack. Of course this does mean the user would have loads of mods installed that are potentially not being used, but from a server admin point of view that's their problem not mine
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