What of Childrens Library Cards

The great and mysterious Ender writes :\”I was watching
Hearts in Atlantis, and it appears they used
to have children\’s/adult\’s library cards. What ever
happened to this
neat ability? It was apparently not limited by age, but
minors had to get parent\’s permission. Which puts parents
in control of which class
of books their kids could check out (but the kids could
probably read
anything *at* the library).


Seems like this would be a great help, instead of banning
books, parents could choose when and how to give access to
their
children