I worked for a company that located phones during E911 calls, at the cell network level, without using GPS, down to a few meters. The most humanitarian mission you can imagine. It was golden.

But it turns out, authoritarian states wanted to buy the very same tech to locate undesirable people, record their associates and travel history, geofence them, etc. Also turns out salespeople gonna sell. And that's how you go from an ethical position to another kind. People did quit over that.