Crime cameras for the defense  If the cameras can be used for
prosecution, they ought to be available to lawyers for people
who want to establish an alibi  EDITORIAL We've always been
dubious about San Francisco's crime cameras. Filming everyone
who passes through a public space creates severe civil liberties
problems. There are real First Amendment issues. And as far as
we can tell, the spy cams don't work very well: none of the 178
cameras on Housing Authority property have ever led to an arrest
in a homicide case. Chief Heather Fong told the Police
Commission on Feb. 6 that her officers have requested footage
nearly 80 times but only twice was it at all useful.  From the
first days when the city began talking about installing the
cameras, the American Civil Liberties Union and others pointed
out that all the electronic surveillance on high-crime street
corners would do was drive crime to other places. The commission
has mandated that the cameras be turned off during political
demonstrations, and some criti