First of all, I think that it is a good idea not to "name names." While this person is doing something wrong, it can oftentimes lead to unnecessary fingerpointing and blaming that prevents a solution to the real problem, which is how to prevent against it. As with anything that can easily be used as a tool to annoy people, it leaked, and the person in question will not be the only one to do it for long.

However, there is one thing that confuses me. You mentioned fur color and name changes were taking place. This does not fit the packet editing thing. You see, when a packet is transferred, only the necessary people receive it. It goes from the server to the client or vice-versa. No other clients generally receive it. Therefore, things like fur color and name changes are genereally local client-only. Could you clarify what you mean by changes in name and fur color?

The blank line trick unfortunately is fairly ineffective. It prevents against spamming by bots that use a blank name, but not all do. I do not think this is packet editing-related, anyway. It can easily be done (unfortunately) by numerous popular launchers. Doing this blocks those. Some hosts may like this method, some may not care, and some may not want bots blocked from their servers. Besides, because other bots use different names, it is not highly reliable.

The best course of action for now would probably be kicking and/or banning the offender. This is a new and annoying problem and a bit disappointing that it leaked (although, honestly, I am not surprised). Hopefully, this fad will fade quickly.

~ Traft