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.
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.