Most of the researchers in countries like Denmark say that it is a child's play to track your Android device via Wifi when it is on and even in cases when it is turned off and also even if you did not give an app the permission to track your location. Whenever you download an app from the Google Play the need to tell you what all permissions they need in order to function. Something which is very simple like torchlight should not require anything more than access to your camera, so that it can use the flash light. Some heavy apps which are more complicated with multiple features might need some more extensive permissions like access to the phone data, location either obtained through internet or GPS or WiFi.
There have been plenty of issues recently when a student from a technical university in Denmark and his team published in a newsletter that the physical location of an Android user can be easily tracked if the Wi-Fi connection is on. No matter whether you give the app permission to track your location or not. The team experimented by making their own app and making it publicly available on Google play. The app is very small in size and installs quickly on a phone. The only permission the app asked for was access to Wi-Fi. The team members disabled the Wi-Fi and turned off the location data just before installing the app.
At the first few minutes, the app did not work as it could not connect to any data source to work with. But later on, when the app s checked after around 50 minutes, the team got a message saying:
The network office, which was very precisely located, via an app which did not have the permission to locate the physical presence of a user. Maximum of the most downloaded apps on the Google play has this capacity. Such apps include big names like Candy Crush, Pandora and Angry Birds.
It doesn't necessarily mean that these or any other such applications collect your Wi-Fi data for tracking your location. These apps however are capable enough to track your location precisely and accurately. They simply break the Android's permission model and the general public understanding. This way you can never really rely on Google and Android. They actually do not respect your privacy.
There was another research work, 65 people participated in it for a period of over 200 days. The results were that it was very easy for ask these apps to identify the workplaces, home, schools and such places.
Therefore it becomes very much necessary for you to understand what these apps are doing with your location information.