FaceStation has a feature called a proximity level. This is a feature that allows you to set the distance in which the user will be scanned.
If the proximity level is set as near, only users close to the device will be scanned.
If you set it to far, the device will attempt to scan even when the users are further away.
You might want to set it to near if the device keeps trying to scan people who are passing by the hallway and that is not desired.
You may be curious how close 'near' is and how far the 'far' setting is.
There isn't one simple answer for that.
FaceStation's sensor senses the object with a infrared light so the distance that is sensed would differ based on the installed environment.For instance, a user with a white clothing on would have a different scan distance than a user with black clothing on.
Furthermore, if there is an object on the other side of the hall that reflects IR light such as a mirror, the scanned distance would differ as well.
Therefore you should tweak the settings as necessary based on the situation of your installed environment.