They pick up on everything. Also, however, children of alcoholics often do whatever it takes to get attention-- even negative attention. This quickly can manifest as self-destructive behavior.
In my case, all my attention was taken up by my alcoholic wife and her ********, and protecting my daughter from it. A side affect of this was that my daughter subconsciously noted that the way you get attention from me is by being a ********.
We are trying to break out of that dynamic now, years later, and it's very, very, very hard.
Cyranoak