Wouldn't you need a hand strap in order to open your hand without dropping the controller like you can do with the Valve Index controllers? Without one I suppose you can do gestures to a certain degree.
I think there's guesswork involved. I mean, there's only so much your finger and thumb can be doing if you take either off the controller.
So they can probably simulate you pointing just because your index finger is not touching the controller. That's my guess anyways