Someone who's still playing after 10 hours hardly fits the "people with low playtime" category. People with limited playtime are generally only going to be in one or two queues in a day, so won't withdraw (or be withdrawn by a teammate) from three of them. And for days when people are playing all day long, a 30 minute penalty doesn't amount to much, at least not for such a rare combination of occurrences.
(Note: This doesn't mean I disagree with the thread's point. I do indeed think it's rather unfair to be penalized for something somebody else did. I just think the problem is a minor and unusual one.)