[microgood]

The police often detain them long enough to get their ID because this discourages them from coming back and encouraging problem behavior in these neighborhoods, which the law abiding residents do not like. The residents often request this from “community policing” programs.

True, but it does not make it legal. And without reasonable suspicion, it is not.

[livius]

The reasonable suspicion is that a resident called in. Soliciting prostitution is illegal, and so is purchasing drugs.