For appropriate reasons, I know the 'ghost' ban thresholds are secret (otherwise it would be incredibly easy for script kiddies to simply game).

However, the hacker in me is almost curious enough to see how far I could "poke the lion with a stick". If I had more time, creating a few dozen accounts ... etc

Then I think about how I would engineer such a system and try and keep it as automated as possible. I'm sure its well written enough to threshold on some dynamic curve based on incoming traffic.

And, whilst variety is the spice of life and all that, if you are a prolific (and popular) poster, should people care if you self promote. If each of your posts is a winner, generates great readership figures and 'likes' and spikes conversation, why not allow this? So, I'd want to deviate down a score based on popularity. Then there is frequency of posting, and comment karma ...

At the end of the day whenever there is a threshold, there will be edge cases where people are the wrong side of judgment line. Banning is a digital thing, and reputation is analog. I'm glad that hn seems to have a response appeal system.