Why can't you re-register the event? If you do it at start up, no one will be in the server and the new clients that connect will get the new registered data.
You could call:
registerOutputEvent(Bot, "SetRandomAppearance", "List City 0 Space 1 Enemy 2",0 );
Then package:
function AiPlayer::SetRandomAppearance(%this,%type,%client)
{
if(%type < 2)
return Parent::SetRandomAppearance(%this,%type,%client);
//Do stuff here
}