I was partly shadow-banned myself, on this account -- my comments would show up, but not my submissions. I only figured it out months after it happened (I just assumed the things I was submitting weren't catching peoples' interest for some reason), which was frustrating. At the time the account had more than 4,000 karma, which I would have thought would have been a decent indicator that I wasn't a troll.
I eventually got the ban lifted, but only after writing HN and asking them to do it. I never got any notice that I'd been banned, or really any rational explanation about what I'd done to cause the ban, either by email or in a thread, from HN admins or anyone else. My profile has both an email address and a link to an "About Me" page with my contact information on Twitter, Facebook, LinkedIn, etc., so it's not like I'm hard to find.
Even though the ban eventually got lifted, it really knocked my opinion of this community down a few notches. Passive-aggressive measures like hell-banning/shadow-banning/etc. should be last resorts used for silencing hard-core trolls. If they're used too widely, they break down the trust a community needs to have in its mods to function properly.