piss cookies, you say?

Sorry - I meant "permission", not cookie. If this is on (for Bluetooth headphones, sharing content, smart home etc) you could be leaking your location. If your partner shares their location, and you don't - but you do allow your phone permission for nearby devices - your partners phone is revealing their own location, and their proximity to to you (your location). Third party cookies can be relevant for this because they allow browsers to identify/differentiate other users on the same network. If one user shares their location (or their location is known by the site they visited), then the other users on the networks location is also obtained.