[fraa-orolo]

> I'd say when the data is observed is when it becomes surveillance.

If I recall correctly, that was exactly the US government's defense after the 2013 Snowden leaks revealed it was tapping every internet connection possible and sucking in every piece of data available.

[betterunix2]

It depends on the meaning of "observe." What if the data is secret-shared among many independent parties, so that no single party (or even a group of parties smaller than some threshold) can process it in any way? This is a common model for using MPC to protect privacy while collecting user data; in fact the first real-world MPC deployment was organized in this manner.