Turtle, your thesis is well written and on the surface makes sense. I have to stick to my original position though because some people in this world are too unstable to "speak to". Some would just as soon punch you in the nose as breathe for having the gall to "speak to" them in that kind gentle manner you suggest. Some would respond in some way or another and then watch you and do something to your vehicle when you go inside.
When you see other drivers, you kind of know which ones are in the mood to talk and which ones aren't. The ones that aren't in the mood, it's not a good idea to confront them, gentle or otherwise. We all need our space out here. But, if you first start a conversation with the usual small talk, you can quickly determine what they're all about. "Hi, how ya doin'? Ya been busy?" the usual stuff. If you get curt, one-word answers, and they obviously don't want to be bothered, they aren't likely to be receptive to much of anything, least of all a pee bottle favor. Pick your spots.
Now, if the guy's curtain happens to fall down and you see him inside with his bra on and call it in I'd say you are a tattle tale. If you are calling to report citizenship problems you are just being a responsible citizen as opposed to his bad citizen.
There's a fine line between tattling and being a good citizen in many cases. I think it's well defined in the KGB's Guide To Being a Good Citizen, though.
For the most part I mind my own business, expect others to do the same, live by the Golden Rule, and try not to judge too quickly. So far so good.