Surveillance in public areas is very effective, 6 Crimes a day solved by cctv, this shows how mass surveillance has benefited society. For example, the infamou London Nail bomber was solved in part by a cctv footage. If it weren't for cctv cameras many crimes would take much longer or be impossible to solve, allowing the perpetrator to attach again or not be brought to justice.
“lives have been saved” because of the cautious execution of the surveillance systems. “We know of at least 50 threats that have been averted” not just in the United States, but in countries around the world, including Germany.”
-Quote From National Security Agency Director Gen. Keith Alexander.
We should give up privacy for the security of the nation, as it helps solve and prevent crimes, helps ensure your individual safety and the safety of a nation and its allies. For example, the PRISM surveillance system of the NSA has help stop 50 terror and crime threats not just in the USA but also in countries like Germany.