Probably well under development, another tool in the kit for some situations.
Makes sense to minimise casualties (on your side at least !).
The other team will be doing similar for sure, drones would be a terrorists dream too, there have been many instances of them being used or developed by such groups.
The modern armies of the World have a terrifying arsenal of weapons already, you only have to look at some of the incredible tech they use for everything from small arms to heavy weaponry like artillery and bombs etc . . . a shame mankind will never get through this desire to be kill each other should the desire arise.