... Although I as well as almost everyone else sort of hate being spied upon there really is a vast upside to knowing what people are up to. ...
You seem to be implying that the loss of some privacy is worth the perceived safety society might get from it? Really! Then why not give up all privacy because it would benefit society so much!. That people don't understand the "right of the people to be secure in their persons, houses, papers, and effects" is a fundamental right. Not violating that right is worth any perceived, or even real, danger to society.
"OMG he has kerosene and fertilizer in his garage he must be planning to use it for bomb making! We must investigate and watch him."
later
"OH the kerosene was for a heater but he was using the fertilizer to grow pot so that's why we did the raid and how his wife and dog got shot"