Playboy, 529 U.S. at 826.  Similarly, in this case, the government has offered no evidence comparing the effectiveness of blocking software and alternative methods used by public libraries to protect children from material harmful to minors.  Finally, there are other less restrictive alternatives to filtering software that further public libraries’ interest in preventing patrons from unwillingly being exposed to patently offensive, sexually explicit content on the Internet.  To the extent that public libraries are concerned with protecting patrons from accidentally encountering such material while using the Internet, public libraries can provide patrons with guidance in finding the material they want and avoiding unwanted material.  Some public libraries also offer patrons the option of using filtering software, if they so desire.  Cf.  Rowan v.  Post Office Dept., 397 U.S. 728 (1970) (upholding a federal statute permitting individuals to instruct the Postmaster General not to deliver advertisements that are “erotically arousing or sexually provocative").

With respect to protecting library patrons from sexually explicit content viewed by other patrons, public libraries have used a variety of less restrictive methods.  One alternative is simply to segregate filtered from unfiltered terminals, and to place unfiltered terminals outside of patrons’ sight-lines and areas of heavy traffic.  Even the less restrictive alternative of allowing unfiltered access on only a single terminal, well out of the line of sight of other patrons, however, is not permitted under CIPA, which requires the use of a technology protection measure on every computer in the library.  See CIPA Sec. 1721(b)(6)(C) (codified at 47 U.S.C.  Sec. 254(h)(6)(C)), CIPA Sec. 1712 (codified at 20 U.S.C.  Sec. 9134(f)(1)(A)) (requiring a public library receiving E-rate discounts or LSTA grants to certify that it “has in place a policy of Internet safety that includes the operation of a technology protection measure with respect to any of its computers with Internet access . . . .” (emphasis added)); In re Federal-State Joint Board on Universal Service:  Children’s Internet Protection Act, cc Docket No. 96-45, Report and Order, FCC 01-120, 30 (Apr. 5, 2001) ("CIPA makes no distinction between computers used only by staff and those accessible to the public.").

Alternatively, libraries can use privacy screens or recessed monitors to prevent patrons from unwillingly being exposed to material viewed by other patrons.  We acknowledge that privacy screens and recessed monitors suffer from imperfections as alternatives to filtering.  Both impose costs on the library, particularly recessed monitors, which, according to the government’s library witnesses, are expensive.  Moreover, some libraries have experienced problems with patrons attempting to remove the privacy screens.  Privacy screens and recessed monitors also make it difficult for more than one person to work at the