A problem arises, however, when what appears “brazen” to people who have already interacted with a community for a long period is not so obvious to anyone else. Many community standards (such as “nice”) are nebulous and have vastly differing thresholds and signaling methods, and this is not something that can be easily resolved up-front. Applying subterfuge early in the process makes it possible for a well-meaning entrant to randomly lose by misinterpreting things early on, then being denied feedback that would allow them to make a more informed decision about their behavior. They are further punished by throwing their participatory resources into an invisible hole while thinking all is well. This is easily nontrivial collateral damage, depending on the set of visitors.

This. I've seen some long, serious, insightful [dead] comments which turned out to be from users hellbanned quite a while ago. If they aren't deliberately trolling, tricking them into continually wasting their time this way is a terrible thing to do.

Parking your car so that it blocks the alley is a terrible thing to do. Eating all the skin off a bucket of fried chicken is a terrible thing to do (as is buying a bucket of fried chicken). Serving warm beer is a terrible thing to do.

Failing to welcome the comments, well intentioned or otherwise, of someone who had to be explicitly driven out of a community is not a terrible thing to do.

Not all of those [dead] comments are actually from hellbanned users, are they?

Then tell them to leave. Don't waste their time.

Why? So they can yell at us? Because we owe them?

How about, the ones who care enough to put contact info in their profiles, you can reach out to them and say "you may not have noticed but the HN admins seem to have banned you".

We don’t owe them. Lying to people is just wrong.

I have contacted dead accounts in the past, a problem is that it’s hard to get contact info.

Hellbanning spambots I can understand. Hellbanning people?

I have sent dozens of those emails over the years. It's only a small fraction of the [dead] productive comments I find, but not that many people have contact info or googleable usernames.