[papaf]

You can't even leave your mobile at home accidentally - that would trip alarm bells, especially if your contact does it at the same lunch hour.

This is straightforward to spoof. A single programmer could do it if they cared enough. It is possible to change the GPS (GNSS?) HAL to send any information you want [1].

[1] https://www.pathpartnertech.com/all-you-need-to-know-about-g...

[giansegato]

You would need to also consistently fake location data inferred from cell towers, which I guess is a bit more difficult to spoof.

[lifeisstillgood]

I am dubious - not that I can't learn to alter my (android) phone so it thought it was in London when really it is in NY - but that I would not be tripped up by correlations. It would have to be a slow sensible variation, it would have to be within the correct cell - London / NY would not work - plus other dumb stuff that I simply don't know about radio propagation or being seen on a CCTV camera etc.

Nothing about spying is ever going to be simple. Especially building those vital human relationships.

[laurent92]

The motion sensor has to keep moving. Apps don’t need permission for the motion sensor, they can freely send it over, it’s not private data.

[zibzab]

In android they have to ask for it first ?

[GFischer]

Pokémon GO had that problem. Lots of "flyers" hacked their GPS for fun and profit.