I've got no dog in this hunt anymore and certainly no apologist for the Liberal government or CRA, but CRA's position has technical merit. Section 6 of the Income Tax Act taxes "benefits of any kind whatever received or enjoyed by the taxpayer in the course of or by virtue of employment". The law provides a list of excluded benefits, but discounts are not listed.

Traditionally CRA did not tax minor discounts provided they amounts were reasonable and did not exceed the cost of the product to the employer.It is absolutely irrelevant that such discounts were part of a collective agreement..... in fact, such discounts should be taxed. The CRA position was an administrative position and they are free to take such positions in administering the law even if they do not accord with the law. Equally, they are free to change such positions, provided the new position is supported by the law. The recent change in position was.

That doesn't mean it was good politics or policy. It fails on both.