Tourists see me with a photo bag, a tripod etc. and think "this might be the right person" and ask me to take their picture.
They give me a small piece of plastic with a small LCD on the back.
Believe it or not, you have to keep this in front of you (between you and the subject) and look inside the little LCD to find traces of a composition. There usually is too much ambient light and the image is very confused.
The LCD thing also has some flashing points that probably mean the camera is focusing on the wrong place.
When I see the picture after the fact, it is usually awful. Tilted sideway, half-heads cut or feet cut away or something like that.
I know I blush while offering to take another.
They usually say "fine" and go away very puzzled, or happy that somebody with a complete gear set was not able to compose a picture decently.
They probably think: "next time I'll ask someone younger".
One has to get a bit accustomed to anything new, no matter how easy it is to operate it.
I face the same issues. Typically though the people who hand me the camera have very low expectations.
I do love handing someone a Holga to take a shot of me. "put me in the middle and push the trigger"
Mark Barendt, Beaverton, OR
"We do not see things the way they are. We see things the way we are." Anaïs Nin
No problems with me if somebody identifies me as a photographer and asked me to get their pic. In recent times I've been asked "hey mate, can you take a photo of us please?" and expecting to hold a camera, find myself holding an iPhone or any manner of peculiar contraptions, but not a digital camera or even a film camera. This has been the case on 5 occasions recently. I'm concerned the OP's title, "It's no fun being a film shooter" is having an undesirable effect on the wider population...
Many people don't know how to use a manual camera. That has been for a long time, but before one needed a little bit more involvement, cameras having a more rudimentary automation.
I remember being handed a blackberry by a classmate to take pictures of them. I was struggling with the thing (shutter lag and lack on responsiveness), she said to me: "I see that being a photographer is not your thing!". However, I've never talked about photography with them, neither they do know it's my hobby. Smartphones might be decent for snapping, but quite frustrating!
And from that same person, I handed my digi P&S to another classmate for a group shot. It was a bit badly framed, with some hair cut. "I quite liked the pictures that your camera made, now not so much"
Well, I guess that handing them an unmetered manual camera would be a sweet vengeance.
Back on the topic, I think that presetting the camera and giving general indications is ok for the touristy grab asking. About your friends, perhaps is an opportunity for some teaching/learning.