What would happen if someone put "www" in their web host name? I mean, it's apparantly allowed, with 3-16 characters. I'm just asing this qeustion as a "what if" sort of thing? XD

That's disabled at the DNS level. www, ftp, mail, cpanel and a few other subdomains are hard coded to go to a certain places and are not forwarded to the free hosting servers.