I had no idea of this rule......
Evidently a new inception as it appears there are a few who did not know of the rule. Also seems as though you have to leave at least 10 minutes in between posts as well.
If they want to have the rule then fine BUT at least format a standard for it such as - "Your restricted for 48 hours" or "your restricted until you have left 20 posts" AND let people know in advance, to me that is just a courtesy.