I'd surprisingly prefer storing all data indefinitely and not allowing users to delete what they submitted if and only if you also eliminate any way to group lo

I'd surprisingly prefer storing all data indefinitely and not allowing users to delete what they submitted if and only if you also eliminate any way to group locations by a device. This data is just too dangerous, even in spite of innocuous intentions. Data breaches happen, National Security Letters remain threats, and targeting ads based on a user's current location will tempt anyone. You will fill your users with confidence if you remove your ability to group the data points. Moreover, you shouldn't discount the importance of historical barometric data. At some point, it might no longer be practical to store the data in its most atomic state, but maybe rolled up to a periodic snapshot (maybe hourly) of some geographic region. What data would you be looking to store for longer than a month?