The Northrop Grumman X-47B and BAE Systems Taranis are both delta-wing triangles.
Heck the NG bird is being developed for the Navy, finding one flying around Naval units would not be surprising at all. Not telling every squid on every ship every thing that is going on, also not surprising. The BAE bird was merged with a Dassault program and they are still trying to develop and sell it. Wouldn't be surprising to have them putting it through it's paces as a demo.
So, if I’m understanding your theory correctly, Northrup Grumman - or some other military contractor - was testing its highly secretive drone technology in well-traveled commercial and recreational navigation channels. This drone tech is a fixed-wing system that is capable of operating 100-miles from shore, loitering over a target for close to two-hours and moving at speeds at 15-knts (or less). And, they’re going to do all this ‘testing’ in the presence of one of the most advanced warships on the water today so that the highly secretive advanced drone can be photographed with infrared, latest generation NVGs and optical cameras with most of the footage that was produced can then can FOIAed for public release?
Is that about the sum of it?
Why in the world would any defense contractor want to announce to the world these kinds of revolutionary aeronautical advancements in remotely-piloted platforms?
We have UAVs that can move quickly. We have UAVs that can operate at very high altitudes. We have UAVs that can loiter on station for an hour or so (if launched nearby) and at very low altitudes. We have UAVs that can hover or move at very slow speeds.
We don’t have UAVs that - in the same package - can do all the above and more. Such technology would be one of the greatest - perhaps the greatest - advancements in aircraft propulsion and aerodynamics since the Wright Brothers.