We’re at a unique time in the history of surveillance: the cameras are everywhere, and we can still see them. Fifteen years ago, they weren’t everywhere. Fifteen years from now, they’ll be so small we won’t be able to see them. Similarly, all the debates we’ve had about national ID cards will become moot as soon as these surveillance technologies are able to recognize us without us even knowing it.

Bruce Schneier, “Remote Scanning Technology”