Hm. Should be like in other games then. No login account, not able to play.
That's up to the server admins. sv_login 2.
That doesn't stop people from registering multiple accounts, though. I can only do so much to prevent that. I'd rather have people evading ip bans than cluttering up the database with hundreds of accounts to evade bans. Naturally I can't block certain IP's from registering accounts if they are dynamic. If they aren't dynamic then I wouldn't need to do anything more than an IP ban to begin with.