Are skinchangers banned?

Are skinchangers banned?
I just played with a skin changer, and my friend got banned.
He says that he did not use cheats, only skinchanger..

They are. They've been for years. How have you not heard about this?

Yes they are. I dont understand pepole who uses that. It's only on the client side. So only you can see it.

Of course, they mess with game files so yes VAC detects them, graphical mods are also banned.

As the others said yes, but just think for 1 minute about it, some skins cost thousands if not tens/hundreds of thousands, why would Valve allow you to get the skins for free?

It's only on the client side. So only you can see it.