So here’s the problem. The “Ignore” feature in Discourse doesn’t completely hide the other person. It makes their messages invisible (and actually does a really brilliant job at that)… and replaces them with a link that says ‘VIEW x HIDDEN MESSAGES’… this is something I can easily hide with CSS, so no big deal.
BUT! If someone has quoted a blocked user, you still see their avatar and name (but not any of the quote itself) on the message, and you also still see their avatar and name in message reply indicators. Crap.
That means that if User A blocks user B on my site… and I do the double-ignore trick (ignore in both directions) as I described in my previous message… then user B (who never themselves blocked user A) is suddenly seeing some weird stuff where User A is posting on the forum. And can figure out that User A has blocked them. So now that reveals private information (who user A has blocked) to user B. Which on my site is not good… at all.
Ughhhh
So I guess I’m at the point that I probably need to learn RoR finally 
and write a plugin that extends the existing “Ignore” functionality to really, really erase all traces of a user on an ‘Ignore’ list. Then I can go back to my double-block idea…