Oops, I didn't make myself very clear. IMO, a ranking system would not necessarily play a part in a game setup. Make it optional, so that 'any rank' games exist, but also games for low rank or only high ranking players. More or less just as an optional feature. But even if there is no button in the game setup to limit ranks, a little info besides the server about the ranks of already participating players would make things a little less frustrating for newcomers.
Edit: Idiot that I am I misunderstood you. Of course, you are right. There should be an option to have a game not influence the ranking. Sure. My guess is that most players would just let ranking happen, and actually turn it of when fooling around. And if someone doesn't like it at all, why not have an option in the players option screen ? Just list him as not having a score in the game tab.
My idea is really just to give new players/casual players a good idea of what kind of enemy they are encountering in multiplayer. Ranking seems good for that, but other options sure might work as well. It might even be a good idea to just have a flag set in the server options 'Careful, not exactly new player friendly game...'. Or have an option 'advanced player' in the option screen on the client side, so that players can give others a rough idea about thir own skill. Actually, might even be the easier option. Perhaps just have the game ask after a few dozen games if the player would like to set the option now or not, and then do not ask again (in case the player only sees it as nagging).
Cheers,
E.
