There are rumours that these drones came from a Liberian-registered-but-actually-Chinese oil tanker. The performance of these drones, if accurately reported, would be far in advance of anything commercially available; but it is not impossible that military drones could be much more capable than over-the-counter drones.
I'm not convinced - there have been many cases of distant aircraft and stars mistaken for drones in the past, but even if these particular sightings weren't drones, the technology is improving so rapidly that I expect to see a myriad of flying robots everywhere in the (relatively) near future.
Regulating these craft will be a nightmare - but quite possibly advances in tracking and information technology will be able to untangle this problem eventually. Every drone will need to have a transponder of some sort - and rogue UAVs should be relatively easy to detect because of this.