There's already much finer granularity in stores, thanks to wifi-based tracking (even if you don't join the network [1]), so this ship has sailed.

Refining GPS accuracy only modestly improves the ability to track what stores you are near. Wifi-assisted GPS tracking that exists today probably tells advertisers everything they need to know already.

http://www.nytimes.com/2013/07/15/business/attention-shopper...