Wikipedia recently banned the United States Department of Justice from editing entries after discovering that someone from inside the DoJ made a questionable edit to an article.
The article that was edited was for the Committee for Accuracy in Middle East Reporting in America (CAMERA).
Recently, CAMERA came under fire for supposedly planning on editing Wikipedia entries to support their cause and views. Then, someone at the Department of Justice removed mention of that scandal from CAMERA's Wikipedia page.
The ban has since been lifted, but again, it raises questions of Wikipedia and the validity of its information.
The Register: US Department of Justice banned from Wikipedia