As someone pointed out (and I should’ve mentioned earlier in the article): yes, Valve have a system for registering servers with Steam IDs.

But there’s two problems: they haven’t done any enforcement action ever, and server owners have access to massive amounts of burner accounts.

edit: I've now updated the article to mention that in the main body of the text.

If they start banning everyone that does it even those operators will rapidly run out of burner accounts. Can’t keep justifying $30 for every CS purchase if it’s going to be banned a day later.