Tough question....obviously, there are offenders who made one mistake and really intend to abide by laws & community standards.....and others who cannot be trusted 5 minutes out of jail. It seems unfair to apply the same restrictions to everyone, but how can you know?

I'd like to see a "ONE offense in a library" (including approaching a child or accessing porn on a computer) and you are banned from the place. Perhaps they could have implants like price readers, and libraries have a sensor/reader to alert staff? I dunno...but if 62.417% are just wanting to use the library for reasonable purposes, I'd hope a way could be found to allow them, but keep the staff aware.