Wouldn't it be better strategy to be as public as possible with this? To start a competitive situation where prospective acquirers would want to get to the tech first before their competitors?
I doubt you'll notice this but blacklisting new users like me -- so that my comments are always shown at the bottom of a thread and never publicly -- has the opposite effect of what you're intending. It pushes good people away.
Good people won't keep creating new hackernews accounts to figure out which combination of HN activity won't blacklist them. They'll leave. Possibly taking HN's users with them when they create the next HN.
Like Oculus did and got bought by FB.