You have not answered why numbers on social behavior are knowable.
Funny you should bring that up, as I was just thinking of this one personal experience of mine earlier today.
A few years back, one of my best friend's younger sisters had a problem with cocaine. Her "friends" knew this, but kept selling her blow. My friend and I ended up beating the living crap out of the "friend" of hers that was selling it to her and let her know that anyone else dealing to her would meet a similar fate.
Word got around and people stopped dealing to her. She now does not use and is a successful adult, due in part to our efforts. The government did nothing that prevented her from partaking.
I never said they did. But laws against drugs assist parents in their efforts to keep their kids off drugs.
"You have not answered why numbers on social behavior are knowable."
You can compensate for those factors in a survey.
For example, you're telling me for a fact that kids lie. Fine. What percentage lie, Mr. I've-got-the-facts? Surely you know the answer! I mean, you wouldn't make that statement without knowing what you're talking about, would you?
Now, armed with this precise information from you, I can apply it to the survey.