I disagree with this assertion. Shadow-banning on HN is quite well known, and any troll worthy of the term understands the landscape of their endeavors.
>banned regularly so it effectively doubles their work
How is opening a link once a day or so in incognito mode to check for their comment effectively doubling their work?
>Quite often their willingness to invest time into trolling drops off with lack of response so often they will leave before they understand that shadow banning is a thing.
Again, I think we both have very different ideas on the transience of a trolling campaign. I assure you, once someone is determined to troll a specific community, its a much longer commitment than you are estimating.
Edit: Impressive. Down-voted for stating my disagreements with counter-points.