T-Mobile’s Web Guard filter is designed to help “restrict access to adult web content on your family’s T-Mobile phones.” Sounds simple enough right? Well, according to the Open Observatory of Network Interference (OONI), sometimes the blocking tool works a little better than it should. T-Mobile says Web Guard should restrict access for content that falls under 12 different adult categories, including alcohol, pornography, and suicide. During OONI’s testing, a number of unexpected sites were censored, including Tor Project (an anti-censorship tool), an Italian page that displayed to users blocked by Italy’s national censoring firewall, the website for Cosmopolitan magazine, a Chinese sports news website, a French economics site, a 9/11 conspiracy site, a Greek political blog, along with many others.

T-Mobile readily admits the feature isn’t perfect as its Web Guard FAQ explains the “filter is not error-free and may over-restrict or under-restrict access from the customer’s or parent’s perspective.”

T-Mobile has yet to comment on the OONI findings but we’ll update the post with any T-Mobile response.

The Verge via Boing Boing, OONI

Learn more about T-Mobile Web Guard