I didn't realize Paul Neuhaus' site includes current legislation - great job Paul! This is a terrific up-to-date source - I see it's got Wisconsin's new amendment.
You'll notice a definite trend - several states have or are trying to make similar amendments allowing parents (fairly specifically defined) to see their minor child's records.
Sometimes I'm asked whether parents can see their children's records in California. There is no provision that allows parents in California to see their children's records, although some libraries interpret that as implicit. The more conservative legal position, IMHO (in my humble opinion), is to not allow this, except to give out fine information, which is exempted. The movement in other states tends to show that they view it necessary to make a parent exception explicit and define who is a parent and who is a child.
A workaround for parents who are not allowed by law or policy to see what's on their child's records today is to look it up themselves. If they have the child's card in hand, and the PIN - many libraries let you "see your own record." I think this is a good workaround. Parents of young children get to see what's out to help them find the books to return (the parents probably picked out the books anyway.) Parents of older children do not have the card and PIN. Instead of an arbitrary age limit, it depends on the family's own dynamic as to who is the parent and when custody of a library card moves from parent to child. Not perfect, but not too bad.