I think that's a really important point. Adults assume that kids see and hear what the adults see and hear but the truth is that most of the time these things go right over kids' heads (UNLESS a big deal is made of it, in which case the kid will work hard to figure out what was "bad" about it).
An example from my own childhood... In 2nd grade I had a great teacher whom I loved. She would let us bring in 45rpm records (anyone remember what they were?

) on Friday's and play some of them during our break time in the classroom. A big hit at that time was the song "Afternoon Delight" by Starland Vocal Band. Someone brought that 45 in and all of us little 8 year olds were happily dancing and singing along to the pretty melody when my teacher got flustered and took it off the record player, saying we couldn't play that song. None of us had ANY idea why or what the song was about. The ONLY reason I remember this incident was because she made a big deal of it. NOW as an adult, I know what the song was referring to (though when I told my 65 year old mother this story recently, she said "really? I had no idea what that song was about either. I never really thought about it, just thought it was pretty"

) but as 8 year olds, even singing along with it word for word, it went right over our heads and we would never have even thought about it if the teacher hadn't taken it off the player and told us it was "bad". THEN we thought about it a lot, in an effort to figure out what was "bad" about it, and truthfully I don't think we ever figured it out at the time.