EUGENE ALEXANDER DE KOCK
Yes.  However, it would not have been such a great obstruction, because Shosha did testify regarding certain ANC matters, Tshabalala also testified in ANC matters and I have no doubt that the ANC would have known that these two persons were working for the Security Police, they testified against some of their own people, who were ultimately convicted.
	It wouldn't have been familiar to those in the camps.  There is reference in "The Fog of War" by Van Klausowitz that communication and intelligence systems are insufficient and can give the wrong information to the wrong people, and lead to the wrong decisions as a result.