When I watched "Minority Report", I enjoyed it but said, "There's no way sane people will allow this." I'm wrong again.

http://en.wikipedia.org/wiki/Minority_Report_(film)

I think it's a bit different when they're using it to discourage, rather than for enforcement.

As a side note, Minority Report film was changed in some... interesting ways from the short story. Like, most ways. I recommend reading it. Not that either should serve any sort of evidential purpose...