Earlier quoted context omitted.
When do you differentiate between a toy and a UAV?
The FAA has lighter regulation for drones under 250g, for this reason. But even then, small toy drones of any size are still regulated by the FAA.
Does the FAA have jurisdiction over paper planes? What about the airspace in my house and does it matter if the doors are open?
On the other hand, I don't think government agencies have much incentive to preemptively limit the scope of their authority, but would be happy to hear of counter-examples.