I think a lot of times as engineers we imagine the tech divorced from the reality of the world it exists in. It would likely be politically untenable to start stopping and frisking Wall Street bankers.
And the Wall Street Banker is unlikely to be on his way to a in-person mugging appointment. Rich people usually avoid petty or violent crimes.
It doesn't seem that outlandish, though, that he might be in possession of controlled substances. The point of stop-and-frisk isn't to catch someone "heading to a mugging;" how would you even discern that?
Stop and Frisk is intended for finding illegal knives or handguns.