Effective disengagement, from a friend in Western Europe: "Last week, I was targeted, and actively probed, by a 'street-person' while perusing inside a crystal shop in the 'high-rent' district. The shop's clueless proprietor didn't notice that there was a predator on the prowl in his establishment, but I did!
The sleeze-bag identified me as a foreign tourist, and started circling, trying to stay behind me. I recognized immediately that I was the object of an active stalk. He was apparently not prepared to confront me directly.
Rather, I got the impression he intended to get behind me and go for a quick, hit-and-run job, snatching my wallet and whatever else he could get. I made eye-contact and maneuvered to prevent him from accessing my flank.
That apparently disrupted his plan, and he left the shop, but lingered outside. Upon my exit twenty minutes later, he tried to take advantage of my parting conversation with the proprietor and made a rapid approach, again trying to get behind me.
I stepped rapidly through his spiral, thwarting his approach and orienting my body toward him, as I deployed a blade covertly behind my right thigh and assumed the interview stance. I was prepared to slash whatever limb he used to grab me.
Abruptly, his countenance fell! He precipitously changed direction, and, at all but a run, departed rapidly, venting his frustration on a nearby dumpster before disappearing all together.
Some might suggest that I should have left the area when I first noticed this creep, but, at least in this part of the world, when one adopts that SOP, getting any business conducted becomes just about impossible!
As you've noted, there are no 'safe' neighborhoods.'" Lesson: All of us need to hone our decision-making routine with regard to when to break "stealth mode" and challenge overtly. It's your call, recalling that "tactics" is just "the best of the worst." Disengagement can usually be accomplished successfully through movement, posturing, and verbalization.
Higher levels of force are seldom necessary, but you need to always keep yourself in a position to escalate instantly when required. This response potential includes, of course, lethal force. When your adversary elects to go "all the way," you can never hesitate!