I have a formerly homeless friend who now has a home, wife, job and a family. But he still looks homeless and gets harassed periodically. He knows his legal rights from years of harassment.
He told me that when he refuses to identify himself or explain anything or turn out his pockets, the police get up close and personal. They are trying to provoke a fight response and the consequent justification for arrest.
This is someone else in the photo.
I've never seen this tactic in the U.S., but I expect to see it cross the Pacific.