i have been mounted in public, but not seen.
I was like 23y/o at the time, my family had a truck with tinted glass, the kind that turns a window into a one way mirror.
so one day I took my dog to walk at the park, so when we were there it occurred to me that it could be done without being seen, what I did once we came back to the truck was to take a few rounds around the truck, trying to take a peek inside as I was any pedestrian, and yes, you had to be putting your face to the window and surrounding it with your hands to see properly inside.
so we got in and let me tell you, sex in a car is difficult with a person now imagine with a dog.
it was crazy... difficult, but good and the thrill was amazing.