Using this mod: http://www.minecraftforum.net/topic/467504-125-macro-keybind-mod-v087-updated-for-125/
users can view me while I'm vanished when executing a macro while using the $$u parameter because that parameter is an online list of users to choose from to use in the macro. Would it be possible to add some code to the plugin that hides me from that online list too?

Looks like it's building from the tab list. If someone can see you in the tab list, then they have the permission node vanish.see

No it is not building it from the tablist, they can't see me on the tablist. They can only see me on that macro online list thing.

That's really weird. Time to keep poking I guess.

Maybe a list of cached skins?

I just clicked on the link: So is this saying that the minecraft TAB name autocomplete is actually governed by a request to the server? If so, ew. Time to check every packet to see if I'm right.

N.B. I'm just rambling, I don't have anything to add to this issue yet.

I'm looking at Packet20NamedEntitySpawn, I'm thinking this might be sent to everyone once on login before any canSee checks are done.

In 1.3 tab name autocomplete (and other tab completes) will be done via server request to allow for plugins to autocomplete stuff, or autocomplete commands etc.

That'd be weird, and would be an issue whether running VNP or not.

Packet20 isn't sent until after the join event, and isn't sent for vanished players. If it were, you'd see the entity.

Author confirms it's based on the tab list. Not an issue.

can you change the tab-listname with your plugin? So make out of "Julia" "Notchia"?

This plugin is just for hiding people not changing their name :)