It is like Psyche lighting the oil lamp--before you do it, stop and think!  Not only is it, "What do you want to know?" but more importantly, "What will happen when you (try to) find out?"  

The bill is itemized:  1)  What is the price (consequences) of asking? 2) What happens to you when you have the answer a) because of how it changes you and, b) how it changes others when they know you know?  

In your example you are thinking of a whole technology, and of course the problem is summarized:  How can (will) it be (ab)used?  

To the case at hand:  Not only do cell phones cause brain cancer, but they enable the government--or anybody with money and access--to trace your movements and model your behavior, collectively or individually, to the advantage of . . . who?  What's not to like!