Rapaire – I'm being the devil's advocate here, but I suspect you're stepping into a real mine field in trying to get meaningful legislation passed on any sort of "banning".    There's going to be a conflict of interests if your library's philosophy is similar to our public library's here in a small Montana city.

About a decade ago our library was asked to ban "The Joy of Sex," and then, just this fall, "The Joy of Gay Sex".   The library refused to, and staunchly defended having those books on the shelf, based on freedom of speech and information. One strong argument presented in the library's favor was that parents should be the ones to monitor what their impressionable youngsters were
perusing.

It seems that not wanting to ban "books," but wanting to ban "people" who have possibly already paid their debt to society, is an intellectual conflict.   Also I wonder about the policy of not viewing porn sites on the library's computer – is that not freedom of speech denied ?   

I'm glad my library has the books it has, and I don't want to see anything banned.   I suspect the answer, as suggested by others above, is eternal vigilance, first by the parents, and then by the library staff.

And of course if I found anyone trying to molest my granddaughters I'd gladly castrate them with a rusty pocket knife.