On a tangent: if people do accidentally find indecent images of children, or images of child sexual abuse, there are methods to report those images anonymously.
The Internet Watch foundation is one site. There are probably others for different countries. https://www.iwf.org.uk/
I'm not sure when this section of the US Code became law but back in the 1990s, I was looking at some adult material and I followed a link to some .ru site that had material that was highly suspect. I made note of the domain, closed my browser and opened the phone book.
I called the local FBI office and reported the site. I never heard anything else on the matter. To be honest, I was more worried that it was a honeypot and I wanted to make sure that if they were watching, they knew that I didn't go there on purpose.
The Internet Watch foundation is one site. There are probably others for different countries. https://www.iwf.org.uk/
The IWF has just announced a collaboration with Google, Facebook, Twitter: http://www.bbc.co.uk/news/uk-33844124