It's certainly possible to do, but such solutions already exist for governments and municipalities so I don't really see the point, especially if it's going to

It's certainly possible to do, but such solutions already exist for governments and municipalities so I don't really see the point, especially if it's going to be phone with a mobile app and a power bank attached... I'd easily use Telraam instead since it's a polished, proper IoT device and easily scales.