Tens of thousands of times over six years, the police stopped and questioned people on New York City streets without the legal justification for doing so, a new study says...But as the number of stops has jumped — to more than 570,000 last year from 313,000 in 2004 — the practice has come under increasing scrutiny, from lawmakers at City Hall and Albany and from civil libertarians including the constitutional rights center and the New York Civil Liberties Union.