While Governor-General David Johnston's visit highlights one sore spot in Canadian-South African relations, Ahmed Kathrada and Barbara Hogan are not the only South Africans - or activists or academics of other nationalities - who have been denied entry to Canada in decisions that subsequently came under fire.
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African National Congress Vice-President Nelson Mandela, left, along with ANC delegation members Trevor Manuel and Ahmed Kathrada, right, addresses a press conference April 5, 1990.
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South African Minister of Health Barbara Hogan, right, is sworn into office by the country's Chief Justice Pius Langa at the Union Buildings in Pretoria, South Africa, 26 Sept. 26, 2008.
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Winnie Madikizela Mandela, former wife of Nelson Mandela, casts her vote during the South African municipal elections in Soweto May 18, 2011. She was barred from entering Canada in June, 2007.
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William Ayers signs copies of his book at the All Souls Church, Unitarian in Washington, Monday, Nov. 17, 2008. Ayers, an American academic and former member of the protest group Weather Underground, was detained by Canadian border officials in 2009, and again denied entry in June, 2011.
Gerald Herbert/The Associated Press
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A video technician sits in front of a video screen as British MP George Galloway is broadcast live from New York in the Metropolitan United Church in Toronto on Monday, March 30, 2009. The Canada Border Services Agency advised Galloway, in a letter dated March 20, that he had been deemed inadmissible to Canada on the grounds he allegedly engaged in terrorist activities. The MP has denied such links although he has openly voiced support for the Palestinian cause and was part of a group that delivered financial and other assistance to Gaza.
Darren Calabrese/The Canadian Press
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Northern Ireland's Sinn Fein President Gerry Adams, left, stands with another Sinn Fein leader Martin McGuinness at funeral of an Irish Republican Army commander in Dungannon, Northern Ireland May 11, 1987. Adams was denied a visa to Canada in July, 1986.
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Andre Gunder Frank, a German economist who taught in several countries including Mexico, Brazil, Chile, England, and the United States, was repeatedly denied entry to Canada in the 1970s on national-security grounds.