If you deploy your weapon and use the weapon optics, you are able to use the freelook. That will give you an unrealistic advantage, if you use zoomed optics.
Without the deploy, it isn't possible to use freelook while using the weapon optics.
Update: The issue is partially solved.
Partially because:
If you now press the optics key (default: right mouse button) and press the freelook button (default: left Alt) you can't use the freelook.
But:
If you use freelook (hold left Alt) first and then switch to your weapon optics, you can look around without the weapon on your screen.
The freelook is limited to the movement radius of your deployed weapon, because the weapon will move with your mouse movement. {F25842}