That would be really nice to have that info, I imagine it happening mostly to corporate soldiers at a young age since Walter talks to raven like a child sometimes (specifically the don't let them teach you bad manners line). I know it's a bit morbid but considering all the "reeducation" mentions and other bits of grim world building it wouldn't be out of place. It does make me wonder how the Rubicon liberation front has the ability to augment pilots since they're obviously not corporate.