I do agree with Oci to an extent. Albeit I don't think every plugin that sends messages to players should have ML system support, plugins shouldn't be limited (
hard-coded means something else) inside. That is if the plugin isn't short, of course.
For example, the plugin I sent you
https://forums.alliedmods.net/showthread.php?t=294858 is totally limited to recompiling. That means, if you want to change something, you have to re-compile it. Some people have been sending bug reports and the author hasn't fixed them yet (he's inactive for quiet some time).
@Hamlet
I am sorry but I thought you'd already figure out the #1 post in that thread.