I think some TFLers are mixing what's illegal & what's unethical.
Is S&F legal? Yes. I highly doubt a sworn LE agency with approx 34,000 members would be knowingly doing something illegal or unsupported by the courts.
PC Raymond Kelly has explained what the S&F program is meant to do.
If "corner boys" or dopers are being searched or gang members are unhappy then so what.
If you don't live or work in a high crime area or a place where drug addicts/dealers wander around w/o concern for the law or public safety then you might be more inclined to disapprove of S&F.
Clyde