I got banned as well. In fact, for about five months I got banned about every 14 days, apparently for incurring short bursts of about 4 reqs/sec according to the server logs.

The fact that such a ban simply closes the server connection is pretty weird and unfriendly. For a long time I thought HN was simply down.

Eventually I sat down to search for the cause, and traced the problem to Reeder, the app I use to read HN on my Mac, was trying to auto-discover HN's site icons. It would look for a certain Apple-standardized icon name, and then load the front page if that failed. (When I informed Paul Graham of the cause and solution, he curtly told me to stop emailing him.)

In my opinion the system needs to be improved. The system ought to return a properly formatted HTTP response, and triggering the system should not immediately ban a user for a whole week. I would suggest a gradual system where you initially enter grace period of a few minutes (where the system might reply with "you're loading pages too fast, please try again in a minute") and only ban your IP if you don't honour the grace period.