As I just wrote above: I'm more than happy with the methods of shadowbanning / hellbanning and of URL blacklists.

Noting these more prominently in the HN FAQ, or simply noting that this is a managed site, wouldn't be a bad thing IMO. The black hats have already figured it out, the driven-snow innocents will have their bubbles gently burst, and those of us who've been around the block a few times will just nod sagely.

NB: not to say that some hellbans / shadowbans don't seem to be perhaps misapplied. One thing I've encountered on many systems is that while blocks and bans are features, they don't leave a trace (or much of one) as to when the block/ban was instituted, or why. Google+'s "block" feature (and management of it) are among the worst I've encountered. Reddit's moderation log isn't a complete solution but at least provides a complete registry of what admin actions have been undertaken, by whom, and when.

I'm also a big fan of time-outs, both automated and manually applied. Minutes, hours, days, weeks, months, years/forever.