Even if they do, can still be camouflaged as e.g. a bunch of leaves, or other detritus.

Sounds like an arms race to me.

In any case, the solar cells should still be visible.

(solar cells can be non-reflective black, the reflectivity is just to double-dip the suns rays)

I had no idea, thank you!

Such cells would be half as efficient I suppose, so would need to be twice as large and probably at least twice as heavy. I wonder how that might affect design and payload constraints as it scales.

Or you just wait twice as long, which seems fine for sleeper drones parked on a rooftop waiting for the target to come in range.

How many drones would it take to do that? We’re talking potentially thousands of square miles. The resources required to scan all those areas—and scan them often enough to catch all the drones slowly working their way through—would be monumental.

It would be not unlike scanning all US aircraft passengers to the extent that it is done. At the time, that looked quite infeasible and expensive as well. You would be surprised at how much resources can be diverted to security firms under guise of national security.

My assumption is that it would be several orders of magnitude more than that, but, maybe we’ll find out.