I believe in the somewhat flexible notion of the "reasonable expectation of privacy". So far, this has worked pretty well. No one got hurt
There were a few notable exceptions, though.
I was on business in Thessaloniki, Greece, and hooked up with a very stunning dude. We met, had couple of drinks, talked, and I wanted to take him to my hotel room.
"Nope", he said. "Everybody does this all the time... . Let's do something memorable!"
We drove for close to half an hour from my hotel on the sea shore to a parking atop one of the neighboring hills overlooking Thessaloniki and the Thermaic Gulf. A stunning dude wanted us to have an equally stunning view...
I noticed several other cars. At least 2-3 guys were fucking their GFs. 5-6 other dudes were messing around their respective cars. We went with the flow.
No one approached anyone. We took our time, and stayed out there until the sunrise. Some guys went back into the town sooner. Some apparently stayed even when the sun came out.
On our way back into the town, the guy I spent the night with, commented that "a few people know of this place". No one would openly admit to going there, and fucking around, but people do it all the time. You pretend that the others are not there because you may know them, and because what they are doing there tonight may be very different from what they may be doing there on some other night.