I also thought it was odd, until I started writing an adventure that involved restarting stacks from people killed in the fall. Then it clicked in my mind: the edited memories are to keep them sane. The average reinstantiated person experienced some real horrors before waking out off-Earth. They saw civilization coming to an end, nanoplagues and alien war machines doing horrific things to people around them, and were often scanned in desperate circumstances (I love using the little war memory from "Glasshouse" by Charles Stross as an example). They also lost friends, family members, ways of life and their whole reality. Now, how much mental stress does that produce? And how many reinstantiated just crash into insanity when they wake up and start thinking about what happened? The proper solution is of course slow, gentle psychotherapy. Gradually they learn how to deal with that has happened and realize they have a new life. Unfortunately this requires *lots* of experienced psychotherapists, time, effort and (hence) money. AI therapists are not up to the job, and when you have millions of people to process *now* you will stretch your people beyond the breaking point (treating traumatized people is itself pretty stressful). A quick solution that allows a much less skilled therapist to at least do some fixing, or might even solve the problem altogether, is to give the infugee a bit of retogerade amnesia. You don't even need to fine-tune it to just the horrible memories, just run a psychosurgery macro that removes any memory connection in the hippocampus and cortex that show any sign of not being fully consolidated (i.e. anything new). Do the same with amygdala-related fear conditioning that has any link to them - dampen the heck out of them. If you are being nice about it you save a changelog file that can later be used by the ego and its therapist to restore some of the memories. So the re-instantiated tend to have edited memories: they do not remember much of what happened during the Fall, since that was the cheap way of avoiding direct mental breakdowns. I think there is a great deal of individual variation - some have restored their memories, some were never edited - but I would just allow PCs and NPCs to have some other 10CP disadvantage instead (like neural damage from bad scanning, some mental disorder from remembering it all etc).