The Economist again hits the nail on the head, this time about the draconian and harsh sex laws in America that are being emulated in the UK:
Garsh laws often do little to protect the innocent. The police complain that having so many petty sex offenders on registries makes it hard to keep track of the truly dangerous ones. Cash that might be spent on treating sex offenders—which sometimes works—is spent on huge indiscriminate registries. Public registers drive serious offenders underground, which makes them harder to track and more likely to reoffend. And registers give parents a false sense of security: most sex offenders are never even reported, let alone convicted.
Edit: The Economist has another more in-depth article on the same subject.