Hypothetically speaking enough surveillance plus really advanced compute could find criminals indirectly. As a totally fictional example for illustrative purposes, recall Batman's "cell phone sonar" device.
You don't have to touch technology to leave a footprint. Your footprints are just harder to find.
Edit: I'm not saying it's a good idea, I'm just saying "you can't track terrorists who don't use technology" is false.
It also indirectly enables criminality by eliminating people's ability to be anonymous sources to police or the press. Along the same lines, it grants anybody with privileged (or unauthorized) access to surveillance data the opportunity for any number of truly maniacal illegal acts.
You don't have to touch technology to leave a footprint. Your footprints are just harder to find.
Edit: I'm not saying it's a good idea, I'm just saying "you can't track terrorists who don't use technology" is false.