Tell HN: Regarding the silent banning of HN posters

I think something must be done about the banning system. Most of the people I've seen getting banned weren't posting especially high-quality posts, so I can understand the ban itself - but why ban them silently? I regularly see posts, sometimes obviously long and thoughtful ones, deleted instantly because a user was considered banned - and the user has no idea! Can't the ban be limited in time, or something be shown to the user? I think it's awful to make people waste their time on comments like this.

To show the problem concretely, in the past months, as I read HN I've been pasting in a text file the usernames of banned users that I saw posting in threads here and there. Here are a few examples:

http://news.ycombinator.com/threads?id=tomjen2

http://news.ycombinator.com/threads?id=slavingia

http://news.ycombinator.com/threads?id=access_denied

http://news.ycombinator.com/threads?id=fatdog789

http://news.ycombinator.com/threads?id=robak

http://news.ycombinator.com/threads?id=phil_collins

http://news.ycombinator.com/threads?id=howcool

http://news.ycombinator.com/threads?id=numbchuckskills

http://news.ycombinator.com/threads?id=bugmenot

http://news.ycombinator.com/threads?id=anonjon

http://news.ycombinator.com/threads?id=robak

Just look at the last one. How much time has this person unknowingly spent on posts which all got instantly deleted?