didn't this used to be optional for clients?

[Twisted-Code]

Didn't it used to be that, even if the server has this installed, clients don't necessarily need to get it? One of the players on my server reported that this doesn't seem to be the case anymore, and being the type that doesn't want to make people load more mods than necessary, I'd like to know when that changed and why? Is there any added functionality whatsoever that relies on that change? I can't see any reason for that change other than "annoy the user" (and obviously, that's not it. Leave that sort of thing to the BOFH 😉). What am I missing?