When the subscription is cancelled 'freeze' the existing private data. When frozen it is kept private, but the user can only delete it, or make it public (mayb

When the subscription is cancelled 'freeze' the existing private data. When frozen it is kept private, but the user can only delete it, or make it public (maybe allow read-only viewing, with this possibly limited to the first few slides (or whatever makes sense)). Once public, it is like any other public data in the free tier. This way account status changes neither destroy privacy, nor allow people to take advantage of a loop hole to get free private data.