Purge scheduling I suspect is really very easy to implement. However, like many features that would be unquestionably useful, I left this one out for liability concerns. When it comes to deleting data, I kind of want that responsibility passed down to the admin, because I get enough “I lost data” emails as-is, without giving people the method of deleting.
I don’t really like withholding features for this reason, but above all, I need to maintain my sanity and motivation!