Same. I have never been stalked but had a mother who often invaded my physical territory in unexpected and uninvited ways. Not sure how much that is the cause of my sensitivity to intrusion and concerns about privacy but it is pretty strong, even if not PTSD-like at all. I have known about that tracking tool for a good while and know people who use it. I remember actually feeling angry when I first heard of it, how could someone even create something like that and people use it as though it was a regular communication tool? I would never use it, no matter how curious I am and would probably be quite upset if I heard someone was tracking me that way (probably it happened as I communicate via email a lot) and, especially, if they put demands on me and make assumptions about me based on it. I also do think it is creepy... but then what about the many other ways people are tracked via the internet these days?

I think I would not care much about knowing what a T is doing with my emails but would be furious if I figured, for example, that they track me that way. Just shows a particular type of sensitivity I guess.