Why do privacy experts agree that location data cannot be reliably anonymized?

Human movement is so unique that just four spatiotemporal points identify ~95% of individuals — and location data is collected and sold at massive scale.

Two reinforcing facts:

• It's a fingerprint. Research consistently shows just four spatiotemporal points (place + time) uniquely identify ~95% of individuals. Your home, workplace, and routine make your trajectory essentially one-of-a-kind. Stripping the name does nothing.
• It's collected and traded at scale. Mobile apps continuously gather GPS, Wi-Fi, Bluetooth, and cell-tower data — often in the background. Data brokers run a multi-billion-dollar marketplace, selling to advertisers, political campaigns, law enforcement, and anyone who pays. In the US there's a regulatory vacuum: no comprehensive federal law mandates meaningful consent for location data.

So the patterns of human movement are simply too unique, and the data too widely available, for reliable anonymization (cf. the Burrill case).

Tip: You can refuse to state your religion, health, or politics — but the places you go state them for you.