The warning rule was a disfigured process used by the moderators to track and punish misbehaviour. It preceded the Point System. The system was based on issuing warnings to those who violated the established rules. In principle, three warnings would equate a ban.
The system frequently received criticism due especially to the inability of this system to distinguish minor from major infractions via these warnings and the fact that warnings were not recorded, allowing some misbehaving users to go freely for a long time before finally being banned, while other users only had 1 warning and no other contact until sudden banning.