Last week's Superior Court decision in Silver v. Imax Corporation, 2008 CanLII 34361 (ON S.C.) sets out the test for when a question is proper on cross-examination on an affidavit.
The Court holds:
 Typically, the test for whether a question should be answered in an examination for discovery is whether the information to be elicited has a semblance of relevance to the issues in the action. The same test is applicable to cross-examinations of deponents in motions. In such cross-examinations, a deponent may be asked questions not only about the facts deposed in his or her affidavit, but also questions within his or her knowledge which are relevant to any issue on the motion. Master Macleod in Caputo v. Imperial Tobacco Limited., (2002) 25 C.P.C. (5th) 78 (affd. On appeal at 33 C.P.C. (5th) 214 put the rules succinctly as follows:
* If you put it in, you admit its relevance and can be cross-examined on it at least within the four corners of the affidavit;
* You can't avoid cross-examination on a relevant issue by leaving it out;
* You can't get the right to cross-examine on an irrelevant issue by putting it in your affidavit; and
* You can be cross-examined on the truth of facts deposed or answers given but not on irrelevant issues directed solely at credibility.