An appeal process exists. It's pretty much e-mailing info@ycombinator.com and saying something like "Hey, have I been banned? Please undo!" (if you feel you wer

An appeal process exists. It's pretty much e-mailing info@ycombinator.com and saying something like "Hey, have I been banned? Please undo!" (if you feel you were unfairly banned), or "Hey, I realize I said something that I shouldn't have said. I'm sorry -- please consider unbanning?" In my experiences the people in charge of making these decisions are fairly prudent.