I'll agree that the crimes committed by these individuals took a long time to come to light, but I don't see that either had any relevance to the discussion abo

I'll agree that the crimes committed by these individuals took a long time to come to light, but I don't see that either had any relevance to the discussion about retention of data that could be used to track their movements. Saville didn't escape discovery because there was no proof of his movements. He escaped because those who were harmed by him were cowed into silence, or ignored by those whose job it was to help. As for Shipman, wasn't it precisely because of anomalies in data collected about him that he was caught? And do you agree that collecting clinical data about doctor's use of drugs, and their outcomes vs. statistical norms might be reasonably exempted from the kind of personal data logging that many people find objectionable [me!]