What we keep
AutoTreeGen is designed to preserve not only accepted conclusions, but also corrections, rejected relationships and the reasoning behind research decisions. A merge, a confirmation, a rejected hypothesis and a withdrawn consent are all recorded as events with their time and their author.
Why
A tree that only shows its current state cannot say why a relationship was removed, or that it was ever considered. Keeping the history is what lets you, or a cousin twenty years from now, see what was checked and what was not.