I don't think that's relevant here: the new prompts aren't about collecting gps data but correlating your identity across contexts. If you manually chose a city

I don't think that's relevant here: the new prompts aren't about collecting gps data but correlating your identity across contexts. If you manually chose a city in Facebook, I think the ad in the other random app which used fb ad network would only be able to use it if the user said "yes" to the prompt.