I saw the link, didn't see the proof.  I wouldn't be surprised if it was indeed QS's alt, but I wouldn't be convinced unless there was some hard evidence.  From what I can see in that thread, there's just suspicion.

Definitely not proof--not even good evidence as far as I can see.  The only real way you can link two accounts is if someone admits one is their alt, or with some blockchain evidence, or if someone screws up and posts something from their alt account that was obviously meant to be from their main one.  I've seen that before, but it's rare.