Banning users

How do people plan to handle banning other users? Do you plan to invoke a "three strikes" rule? Issue a warning to the offending user? Strike without warning?

While I remain chief of any tribes my plan is to be open and forthright about any disciplinary action needed against any user, but how quickly they get banned depends on what they do. Violations of the site TOS will result in an instant ban along with a report to the admins on what was done. Trolling will get a warning first, and then a ban. Unrelated/inappropriate submissions will earn a private conversation about why I feel that content is not appropriate and why it was removed, but persistent submissions like it may provoke a warning and then a ban if I feel it necessary.

What's your policy?