What is this about?! Xray?

[Reshe]

The effective plugin could have bugs. Just like towny. Unidirectional bugs for certain mods they may have installed. Such as clear water, etc.

If I'm not mistaken though you would need to remove the meta-inf folder for most every mod, or at lease the ones I've seen. And since he has it that would mean that people with vanilla minecraft are getting kicked. I don't think this is a reasonable conclusion. So either he has a mysterious mod that works with the meta inf that is one-million chance of conflicting... or he reinstalled his jar after having been caught.