We have hunter harassment laws in TX, they would be charged.
On reflection, it would probably be better in the long run to encourage the “anti-drone” industry, to produce several different kinds of countermeasures to drones that would go beyond just a law stopping harassment.
Since right now, most drones do not have encrypted radio commands, this could begin by taking over control of the drone to cause it to fail. Once they begin to encrypt their signals, create a jammer, maybe on another drone, to again cause failure. Then, move to active countermeasures.
While hunters might like to shoot drones down personally, it is also the most efficient way of taking down drones. But there might be an anti-drone gun and ammo that would be optimized for the task.
I can imagine a gun scope that shows a virtual image of a drone, adjusted to take into account its range, vector and speed, so that the hunter shoots ahead of it, the bullet and the drone arriving at the same place at the same time.
Finally, there are the anti-drone, drones. Hunter-Killer drones that would target small to medium sized drones. In concept, they might be somewhat like military Switchblade drones, at least insofar as quick launch and use.
http://www.youtube.com/watch?v=-dgvBb5ke-E