"I mean, people don't get on the bus and read hustler in front of everybody."
I have done this numerous times in public. Anyone asks and I'm reading it for the cartoons.
Also is unfiltered access to computers at a library a good idea? From what I could gather patrons don't even need library cards.
If I start researching bomb making, poison gas, whatever from my home computer I am directly in contact with an ISP that has my name and location.
Now, with the whole "for educational purposes only" bit in mind I don't give a shit if people learn about how bombs work. I do care when they are going out of their way to do it anonymously.
Unless library patrons are jacking off I don't see a big problem with porn on computers. I believe that significantly more than half of the material online is porn/adult. It can't be avoided. Even in University computer labs with no privacy screens I have seen people checking out porn. Not to mention that it's entirely possible to look at porn or offensive images accidentally.
Nearly any topic has the potential to come back with some objectionable images. I would be way more comfortable typing "anal sex" into an image search in public than "diaper rash" (trust me, do not do this).
And plenty of "legit" topics online are going to involve nudity of some sort.
Screens are cool by me but let's check some ID and see who is accessing what.