I'm not an expert, but I don't think this is how
stalking works in practice. People don't stalk random
strangers they meet in the supermarket. They stalk
former partners, and (more rarely) people they've
developed an obsession about.
Well, yeah -- I agree 100% that this is existing predator behavior, and most crimes will continue to be committed by a person known to the victim.However, if not properly safeguarded, this sort of tech clearly can enable some new types of bad behavior.
Ultimately I'm a technology optimist and we shouldn't reject new tech simply because it might be misused. However it's also true that even the most cursory glance at history shows us that just about any new technology is also used for nefarious purposes.
Meet victim in club/bus/supermarket/wherever
I'm not an expert, but I don't think this is how stalking works in practice. People don't stalk random strangers they meet in the supermarket. They stalk former partners, and (more rarely) people they've developed an obsession about. That means the stalker has to worry about being recognized by the victim, and consequently will have fewer opportunities to plant a device and retrieve a device than you imagine.
Furthermore, while being tracked for up to 96 hours indeed is a frightening thought, the typical stalker's goal is to track their victim at all times. Having to plant and retrieve a device at least every four days, without being detected by the victim, makes for a very impractical way to achieve that goal.