It has happened before and it will happen again.
In the early days of internet foras, at about 2000 or so, it was common enough that people changed aliases all the time. It could be rather confusing, but worst was, when many people changed aliases and mimiced a certain maybe destructive style.
Then it was hopeless to find out who was who.
This attempt is not so advanced and the net has matured much since the first days of being the loonetics playground.
Now IP can be traced and first and foremost, people dont bother with all the crap: they want real communication and real people behind the avatars before they listen.