A few points to pick up on here.
We can never un-invent technology so it is going to stay but it does need regulation.
If I can unlock my phone just by looking at it then this seems a reasonable use provided the data is in my phone only and it isn’t calling back to some database to say who is this, and should I let them use this phone.
Governments, in theory, work for us and while I don’t believe there is any justification for mass tracking there may be a justification for limited use. For example if you are guilty of committing violence at a sports game then there may be a case for having cameras at sports grounds at the entrance to check if a known offender is trying to gain entry. The system used must however fail to recognize anybody else and any images of non-offenders deleted quickly. Say straight after the game assuming there are no violent events during it.
We have a system of courts so we should be able to police this with only individuals convicted of a relevant offense appearing on the database and not everybody the police had course to know. For example a theft or motoring offense should not be sufficient to get you added to the list.
Similar arguments apply in airports, we may want to identify people who are barred from travel as they may be using fake ID.
My brother works in my local town supplementing security, and otherwise assisting the local businesses while helping visitors to the town. He keeps a eye out for suspicious activity and those known to have antisocial or criminal history. Informing local businesses and the police as necessary. As far as I am aware the local CCTV does not use facial recognition software, I have been assured it doesn’t, but it is monitored by a person and both my brother and the CCTV operator will notify each other when something or somebody of concern is spotted.
I have an history of political activism, and while it has always been peaceful, I am known to the police. A few years ago I was on a march protesting the governments policies. On a tablet one police officer was carrying their was a picture of my face together with my name.
I should stress two things here: (1) I was by no means the only face - there were 6 on each screen and the officer could swipe left or right for more images. (2) I have never been convicted of any crime, and have no history of violence, but I have been detained during several protests. Would this be a fair use of facial recognition software? I don’t know if any was being used or somebody just recognized me from an earlier event.
I am less comfortable with companies having access to this technology. @sil 's example of music concerts being one idea. I decide to go and see a band, I am filmed collecting my ticket for example. The organizers know who I am as the ticket is tied to my credit card. I expect the organizers to try and sell me tickets to other concerts I may be interested in, though I may not like it, based on my buying history.
Time goes by and I am seen at lets say an equestrian event. I bought the tickets through a different agent so the organizers of the original event have no idea about this. However, the event is televised at a later date and I appear on TV in the crowd briefly. This could be used to target me for totally different types of event.
It does not even have to be facial recognition in some cases. Lets say a company has access to the car registration database and car park footage from several venues. This could tie me to, at least very likely, being present at a particular place and time which could again be used for targeted advertising at least if not something more suspicious.
Android and Bluetooth
I don’t think forcing users to accept geolocation to use Bluetooth is acceptable. There is no justification. I think this is a matter of wording Android could simply say to anyone with Bluetooth enabled and not agreeing to location data
We will not pass on any data regarding your location but when connected to Bluetooth the network may be able to find your location.
I am interested here: does the image depend on what clothes a girl is wearing when photographed? Some clothes are more revealing, at least to my eye, than others. I fully agree that this is a gross invasion of a girls privacy and have no intention of downloading the software to find out.