People don't seem to have a privacy issue when it comes to mobile phones...in theory it's the same as being micro-chipped. All your movements can be tracked by authorities if they have a reason to.
It seems privacy issues only come to the fore if the system being proposed has no direct or apparent benefits to the some people!
You just said it yourself. IF THEY HAVE A REASON TO. They can't get hold of my mobile records without a court order. At the moment, we have a system where everyone is innocent until proven guilty. You go down the road of having everyone's DNA on file, everyones mobile and email traffic monitored and you are basically going down the road of saying everyone is guilty until proved innocent.
Why should I have Police turn up at my door just because my DNA was somehow found at a crime scene even though there is nothing else to link me to a crime. Why am I suddenly in a position where I have to prove my innocence?