According to European law, it should also the case throughout the European Union.
http://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:320...
Policies in the U.K. were also changed last year to allow passengers to opt out, which wasn't permitted before.
The descriptions of passenger screening on the TSA website haven't changed to reflect policy change. Maybe they expect it to be used extremely rarely?
I'd like to write to my Congressional representatives about this, although it's a bit difficult for me to imagine that Sen. Feinstein will be on my side of the issue.
A personal experience from going through on in Germany is that it flagged the passport and boarding pass that i had in my breast pocket which lead to the guy patting my chest like he was a 15 year old getting to 2nd base. The scanner however had no objection to my key chain which I have had a leatherman micra on which technically has a knife (its only 4cm long and is legal to carry even on air travel or at least it was never flagged for me).