Back in the 90's I ran an One Hour Photolab, and we processed many different types of pictures. Some would be of real interest here
One very interesting job that came in was around 100 rolls of film to be processed and printed. We had gotten smaller orders from this fellow, but this one was special. After doing our thing, we saw the pictures were taken out of the US and were mainly of hot chicks posing around some major cities.
Of course, when this fellow came in to pick them up, we had to ask about the pictures. He told us that the girls were just decoys and the real reason for the shots were for the military and government buildings and facilities that were in the background. We knew this guy did work with our government but he never went into who he was doing these for.
I really enjoyed this job because my time in the military was spent doing "spy photos" too. Mostly photo recon stuff, but whatever was needed for a particular project.
I have done photography in one form or another for the past 60+ years, and pretty well know what to take pictures of and what not to. But, basically Photography is not against the law.