Sex Offender Policy

Because of the other story about happenings at the Urbandale, Iowa library I took a look at their website. On their policy page there is a “Sex Offender Policy” listed.

Excerpt from policy: In accordance with Chapter 692A of Subtitle 1 of Title 16 of the Code of Iowa, sex offenders
convicted of sex offenses against minors are prohibited from being on library property or loitering
within 300 feet of library property without written permission of the Library Director.

I am curious how other libraries and states are dealing with the issue of sex offenders. What policy does your library have? Do you agree with the policy? Do you think it is effective? Is a state law or city ordinance the impetus for your policy?