Wasn't the "cheap ploy" tried long ago with a week of Erlang? It probably didn't work as intended then either, but I'm curious if it's just the scale of HN that has changed, or if it's something else, that makes such an experiment seem even more out of the question now.
It worked better than intended! https://news.ycombinator.com/item?id=512280.
I don't think the two cases are comparable really. One was a uniting move while the other turned out to be a dividing move, though we didn't mean it that way. I bet if we appealed to HN to band together against some Redditesque adversary today, it would work just as well as it did back then.
For those who are also curious¹, and the excellent linked topic².
¹ https://news.ycombinator.com/front?day=2009-03-11
² https://news.ycombinator.com/item?id=512291