Dunlop v. The Queen, 2009 DTC 650, 2009 TCC 177 (Informal Procedure) -- summary under Subsection 163(1)

In the first taxation year, the taxpayer did not report income from part-time employment because he had not received a T4 slip (due to a change of address) and, in the second taxation year, he did not receive a T4 slip until around the time of the reassessment of that taxation year and, in his return for that year in the line for employment income, stated "T4 missing from Bulk Barn - will amend when received". In these circumstances and in light of statements in the 2006 Tax Guide of CRA, which did not instruct the taxpayer to include his estimate of employment income in circumstances where he did not have a T4, a due diligence defence was established.