When I say you can't use a scope in this game, I mean you can't do this:
You see, with Alice's current settings (Perspective Camera), you would be looking through the scope as if you were trying to use an ice cream cone as an eye-piece. If you cut the cone in half and looked through the large end, that is effectively what would happen in Alice.
So, closed scopes can't be done in Alice unless the graphics for it happen to be a billboard that you can place in front of the camera.
You
can do red-dots, reflexes, and other open sights, but not ones with enclosures like sniper rifles. In that event I suggest you do it the same way I did in the Tutorial Progress video I made a long time ago.