The Children’s Internet Protection Act (CIPA) was passed by Congress because many issues caused by the internet with regards to things like protecting underage kids from harmful material available online. School and library computers are often used by children in unsupervised settings, so protective measures were called for in order to prevent them from accessing pornography and other inappropriate content.
Schools and libraries now have financial incentives to certify that they are compliant with this law. They need to have an internet safety policy that uses technical protective measures to block obscene web sites. This is a requirement for any library or school that gets money for internet access or internal connectivity via the E-rate program. This program makes communications technology available at a greatly reduced cost, so there is a significant financial incentive to be compliant.
If a school is subject to the CIPA law, they must adopt and enforce a policy that monitors their student’s activities on the internet.
In addition, to quote the federal government’s web site on the subject:
Schools and libraries subject to CIPA are required to adopt and implement an Internet safety policy addressing: (a) access by minors to inappropriate matter on the Internet; (b) the safety and security of minors when using electronic mail, chat rooms, and other forms of direct electronic communications; (c) unauthorized access, including so-called “hacking,” and other unlawful activities by minors online; (d) unauthorized disclosure, use, and dissemination of personal information regarding minors; and (e) measures restricting minors’ access to materials harmful to them.
Before getting any E-rate funding, schools and libraries have to certify that their safety policies and implementing technologies are fully implemented and operational.
If your school or library does not get E-rate funding for anything except telecommunications, then it is not subject to the CIPA law. Also, any authorized person may disable any filtering or site-blocking software if adults need this to enable legitimate research or some other lawful purpose.