Is Google Play Service a kind of "bypass" of my apps authorizations? The google-play-services tag info says that it's "A library used by Google apps and many third-party apps to provide location and social functionality".

Does this mean that if I refuse to provide the location to an app, the said app can still retrieve my location through Google Play Services?
To my understanding, there are 2 way to retrieve the current location from an Android developer's perspective:


The Android framework location API: android.location
This is "the old way" and developers are encouraged to adapt the newer API:
The Google Play services location API.


To access the former, an application has to request permissions to use them:


  Unless noted, all Location API methods require the ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permissions.


To access the latter, developers still have to request the same permissions:


  Apps that use location services must request location permissions. Android offers two location permissions: ACCESS_COARSE_LOCATION and ACCESS_FINE_LOCATION. The permission you choose determines the accuracy of the location returned by the API. If you specify ACCESS_COARSE_LOCATION, the API returns a location with an accuracy approximately equivalent to a city block.


So, no, the service does not offer a way to bypass permission checks. Both ways require the same permissions.