Be a witness.
When you see a policeman talking to a homeless person, smile at him. Smile at the homeless person. Stand there. Glance at the policeman’s badge number. Take a little note. Smile again. You have a right to be there. The policeman should appreciate your presence. If he doesn’t, make another little note. Don’t stroll away until the policeman does.
We’re all going to have to stick our necks out a little now, or have them stretched for us before very long; by the rising tide of lawless homeless and/or by the collapse of the systems they formerly supported with their slavery.