Our public library employees a fairly strict firewall to prevent our patrons from accessing inappropriate content while in the building. Recently, I found out that this method is circumvented by doing an Image Search on any search engine with "Safe Search" disabled. If possible, I would like to prevent our patrons from being able to alter the Safe Search setting on the "big three" engines - Google, Yahoo and Bing.
We do have a server using Group Policy for the machines; however, it currently isn't working properly. We will have new servers in the next couple of months. If there is a way to do this via GP, though, I would happily do it locally.