[sensors] Does Sensor.stop() require user permission?

alexshalamov has just created a new issue for 
https://github.com/w3c/sensors:

== Does Sensor.stop() require user permission? ==
TOC 5.3. Obtaining Explicit User Permission, states that permission is
 only obtained to access sensor readings, doesn't say that permission 
is required to obtain information about sensor availability or to 
interact with the sensor, e.g. call stop().

Consider use-case when webpage got permission, sensor is active and 
providing data, then before stop() is called, permission is revoked. 
Is webpage allowed to call stop()? Should UA automatically stop 
sensor?

Please view or discuss this issue at 
https://github.com/w3c/sensors/issues/146 using your GitHub account