I've recently been assisting a user who is obviously a computer naif; who can mess up even when given step-by-step instructions. So the number of messages back and forth necessarily became large, and I repeatedly got the nag popup. We finally took our discussion off line to PMs because I got sick of the nag.
I feel that was inappropriate and unnecessary because someone else might learn or have their problem solved by reading our discussions.
As I wrote in the post that started this topic, I think this "feature" came from general discussion forums and is completely inappropriate for a support forum such as this one - especially since, as others have noted, the Discourse software is completely incapable of determining whether the multiple responses are followups to try to finish solving the OP's problem as opposed to people just chatting endlessly, which was the purpose of the trap. It sometimes requires multiple exchanges to cut through to the heart of the matter.