No you can't tell, those demos show nothing. There is no proof, and I think it is lame for people to accuse others without adequate proof. If you can tell he is hacking, please elaborate a bit on how you came to that conclusion. I for one am baffled by the accusation. If you'd rather not say why you think he is, then again, you have no proof. I have watched the demos, just to say he is wall hacking without pointing to specific ticks in the demos, or even explaining how you can tell he is wall hacking without the usual signs of wall hacking, is lame, and makes you look stupid.

You don't ban people just because you think they are hacking, you have to have proof, and that is how ibis works, unless the rules have changed.
Prove it, explain the reasoning, OR stfu. Mozart is not my friend either, so that also makes you stupid for the assumption.