I have read every post. It is, to put it mildly, an interesting thread with strong views expressed on both sides. However, something tells me that the vanished OP may well have major trust issues. Certainly, if I found someone prying through my personal emails, and trawling through my personal computer - (without permission) - in pursuit of gaining 'evidence', I'd be livid. Trust is not the only issue here; personal space and private boundaries matter, too.
Re the thread, MacDawg made some very good and thoughtful posts earlier on, (all of which I up-voted) and Arran's later post throws an interesting light on the OP's concept of what is acceptable or appropriate behaviour in a different thread.
The fact that some members (in the earlier posts) seemed to consider it appropriate to post advice as to how emails on someone else's computer be retrieved is............revealing of attitudes to personal relationships.