I wonder if retrieval of the current geolocation in dbg-simulator-actors.js could somehow race this observer registration.

But in any case my more significant concern is that this makes prosthesis retrieve the current geolocation on startup without first prompting the developer to provide it. Whereas in the current codebase we wait to retrieve the geolocation until an app requests it and the developer confirms the access prompt.

Nevertheless, I do see some value in defaulting the latitude/longitude fields to the developer's current geolocation. I'm just not sure how to reconcile that with our interest in confirming that the Simulator should have access to that geolocation.