Sure, if the government was going after someone like Steve Muller (http://www.wired.com/threatlevel/2008/04/gsm-researcher/) you'd want him to be able to keep his stuff from prying eyes.

What about a Suadi National accused of plotting terror attacks in NYC? Would you want the same laws applied to him? Or would you want to able to force someone like this to de-crypt their files in order to stop an attack?

I really don't know what the right answer is, but sometimes laws intended to keep us safe, also give shelter to bad guys.