I know somebody who used to work in a photo lab. He told me that there were drawers full of pictures that they had printed off extra copies of. Any time they saw a picture of somebody naked, they would hit the print button again and make a copy to keep. The customer was never the wiser.
I don't know if this is the full truth or whether it was just drunken boasting. I imagine the truth is somewhat less dramatic. "Drawers full" of pictures? Not likely. But, the occasional extra copy? I wouldn't put it past some people. If they did, you never would be the wiser.
Honestly, if I can develop my own film, why would I ever take film containing nude photos to a lab? I'd develop them myself.
Still, I can't imagine that a commercial lab would ever notice many pictures unless they really stood out.
My job in a theater projection room dictates that I must pay attention to the film and the machines, not the pictures. I look at the images on the film to judge the quality of the film, itself, to be sure it is fit to be presented and I look at the projected image to be sure that the projected image is good enough to be shown to the public but, to be honest, I hardly remember any of the images I saw but I can recall situations that happened while I was working with film.
Assuming a 10-screen multiplex which shows five rounds of movies per day, seven days per week, an operator who does his traditional 40-hour week would thread, run and monitor somewhere between 150 and 200 showings per week. That's potentially as many as 10,000 showings per year.
If an average movie, presented in 35mm., lasts two hours, it would contain approximately two miles of film. That's 20,000 miles.
I worked in the salt mine for a little over 5 years before I was promoted to Technician. My home theater was a 17-plex and I worked full shifts, on average, six days per week. Sometimes, I would work double shifts and there were times when I would go two or three weeks without a day off. If you count this, my time as a technician, teaching employees to be booth operators and the various moonlighting jobs I have had, I estimate that I have overseen the operation of more than 200,000 miles of film.
Our original poster was inquiring about the processing of 8mm movies in a large consumer film lab like a Kodak facility or similar. It's not hard to imagine that a worker in one of those labs would handle orders of magnitude more film that I ever did.
Using my experience as a point of reference, I can't imagine how anything but the most outrageous things would even get noticed, let alone remembered.
Smaller, local film labs and photo shops would not be working under such extreme conditions but I would certainly say that their job is similar. They would see so much film and so many photos that it would take something fairly outrageous to even be noticed.
I would say that stories of people being reported for taking photos of their own kids are outliers.
That having been said, I would still remember the stories told by my friend. There's no telling what could happen to your "nudie" pictures if you take them to a lab to be developed. You could, very well, have pictures of your girlfriend pinned up on the wall in the back room of some shop, somewhere!