If they force the carriers to do it, then they likely have to deal with subpoenas or other documentation. If the government (of any country) does it themselves,

If they force the carriers to do it, then they likely have to deal with subpoenas or other documentation. If the government (of any country) does it themselves, that's way easier - https://infogalactic.com/info/ECHELON https://infogalactic.com/info/ECHELON