It makes me nervous whenever elected people decide to take on a responsibility that belongs to parents. I accompanied my children to the library, and I knew which books they checked out and what they read. That was my responsibility. Perhaps not all parents are equally responsible, but that's no excuse for a legislature or a library board of trustees to take over.
The real irony of this whole situation is that kids and teens have access to just about any information they want to see on their computers and on their phones, including real pornography. Why lock up library books containing alleged/imagined pornography when the average kid has already seen and heard things at school and on TV that I didn't know about until I was in my 50s?