Fair enough, as I said looks like the main feature of this app is to locate a store.
I would use this approach as plan B. User generated contend needs extra effort from user POV and System POV.
I agree on that. It's not mandatory to use the GPS feature you can always go to settings and remove it. As a default setting, as a user, I'd like to have a very fast configuration process (download the app, launch the app, sign in/register and use it!)