ADS-B is not drone specific, but it is very useful to make drones more safe. The problem in the real world is that many pilots of small aircraft refuse to use ADS-B. For some, there is concern about the government tracking their movements, and of course there's extra cost for extra equipment.

There's also concern already that it's way too easy to spoof ADS-B with false data, and that it won't scale well to the number of drones expected to be flying.