Good idea. But I think the main problems is people itself. Look at the post that you quote.
Politics & Society is trash. People go there, look at a headline, and post a few sentences of their first gut reaction without reading any of the other replies.
It may refer to peoples that doing random post, jump from one thread to another thread and didn't even care when someone was quoting their statement (post). They don't want to discuss. They only want to post to meet requirements post of a signature campaign nor to increase their activity count.
People who aware will always hit "Show new replies to your posts." with or without a quote to our message, cause this is a forum, we would discuss with a lot of people isn't with one people only that quoted our messages.