It hasn't happened a lot to me, but presently I am playing someone who has just joined CC. joined four 24-hour games and then gone AWOL. At least in games where the newbie is starting, can they please be eliminated from the game after 24 hours? I wouldn't have thought a player who had done that would be offended to note at a later date that after missing their first ever turns they were bumped from those games. If they are really bothered about their stats they would just reregister. But a freemium with a 4-game limit (and I was a subscriber, under a v old nic, and will be again under this one in all likelihood) might have to wait 5 days to start a new game, longer if there are several opponents. As for any strategic benefit such a player might have been going for, very simply that wouldn't be possible within your first 4 games in your first few days!
So I think it will be of benefit to freemiums, and that it won't make any other difference.
I have thought of an objection, but it is weak: it might leave me with an advantage over the newbie. In that case, another option is to flag newbie games as such and apply the rule to both players.
Or the rule could be that if neither player moves within an hour the game is cancelled. Again, this only applies to games involving a new member.
Interested to hear thoughts.