As the public concern over the Bell coalition website blocking plan continues to grow (both the Canadian Press and CBC this weekend covered the thousands of interventions at the CRTC), the case against the plan resumes with a review of why it is likely that it will lead to over-blocking of legitimate websites. Last week’s post highlighted the probable expansion of the scope of piracy for blocking purposes, a theme that continues today with a look at the many incidents over-blocking of legitimate sites sparked by website blocking (other posts in the series include the state of Canadian copyright, weak evidence on the state of Canadian piracy, the limited impact of piracy, and why the absence of a court order would place Canada at odds with virtually all its allies).

The danger of over-blocking legitimate websites raises serious freedom of expression concerns, particularly since experience suggests that over-blocking is a likely outcome of blocking systems. The Council of Europe Commissioner for Human Rights issued a report in 2014 on the rule of law on the Internet in the wider digital world, noting:

blocking is inherently likely to produce unintentional false positives (blocking sites with no prohibited material) and false negatives (when sites with prohibited material slip through the filter). From the point of view of freedom of expression, the most problematic is widespread over-blocking: the blocking of access to sites that are not in any way illegal, even by the standards supposedly applied.

One of the best-known cases of over-blocking arose in Canada in 2005, when Telus unilaterally blocked access to a pro-union website without a court order during a labour dispute. In doing so, it simultaneously blocked access to an additional 766 websites hosted on the same computer server. The blocked sites included an engineering company, an Australian-based site promoting alternative medicine, a U.S. company that recycled electronics parts, and a fundraising site for breast cancer research. Today, Telus is largely dismissive of the blocking incident with an executive telling a House of Commons committee last week that “if you believe that this is the end of the world and the Internet as we know it, Godspeed. I think actually it is what it is.” Indeed, it is what it is: a Canadian telecom company violating what are now recognized as net neutrality rules by blocking hundreds of websites without a court order.

Yet the real danger is that this is not ancient history. Working with University of Ottawa law students Tanvi Medhekar and Matt Westwell, we identified numerous instances around the world in recent years where anti-piracy blocking resulted in over-blocking of legitimate sites. For example, in 2013, UK ISPs blocked access to around 200 legitimate websites including Radio Times. The blocking occurred as a result of a court order targeting two file sharing websites. There have been many similar instances in the UK including the 2012 blocking of the Promo Bay and the 2015 blocking of CloudFlare customers. In fact, OFCOM, the UK regulator, anticipated the over-blocking issue in 2010 study that noted:

We believe that IP address based site blocking is not granular and is likely to lead to over-blocking. This may undermine the confidence in any site-blocking scheme, and create significant liability risks for service providers. The over blocking property is a by-product of sites sharing IP addresses.

The report noted risks of over-blocking with all technical approaches to site blocking.

The UK experience has been replicated in other countries. For example, Argentina blocked access to over a million blogs after a court ordered blocking of two sites. Further, when Argentina blocked access to the Pirate Bay in 2014, it simultaneously blocked access for the entire country of Paraguay, which relies on Argentina and Brazil for its Internet connectivity. India blocked access to hundreds of sites, including Google Docs, after a court ordered blocking of a streaming site in 2014. In 2012, as a result of an order by the Madras High Court to block copyright content, 38 Internet providers, including Airtel, blocked a range of websites including legitimate content on video sharing sites such as Vimeo. Portugal, which the Bell coalition cites as a model, inadvertently blocked a U.S. video game developer in 2016. Most recently, Internet backbone provider Cogent blocked access last year to sites not included on a Spanish court order and Russia blocked access to 40,000 legitimate sites as it took aim at 4,000 sites on a piracy block list. The year before, a Moscow court issued an order blocking 1222 websites but more than 11,000 legitimate sites were blocked in the process.

There are many examples of anti-piracy measures leading to over-blocking, but over-blocking can involve other content filtering. For example, the Australian Securities and Investment Commission, Australia’s financial regulator, revealed that in 2013 it blocked access to 250,000 legitimate sites after previously blocking another 1200 websites (including the Melbourne Free University) in an attempt to block two websites it accused of fraudulent activity. Further, one UK study found that one in five of the most visited sites on the Internet were being blocked by ISP filters.

The Bell coalition website blocking proposal cites a 2017 UK court decision for the proposition that “there is no evidence of overblocking.” Yet that decision only examined blocking arising from several instances involving soccer streaming and did not review the broader evidence on the impact of blocking orders. A more fulsome review reveals that blocking orders frequently lead to over-blocking, potentially affecting tens of thousands or even hundreds of thousands of legitimate websites. Given the hundreds of ISPs in Canada with varying technical capabilities, mandated website blocking as proposed by the Bell coalition would likely lead to over-blocking of legitimate sites with providers left to shrug their shoulders and note that “it is what it is.”