It's actually the law now; Section 6 of the Income Tax Act is taxes "benefits of any kind whatsoever" that is received or enjoyed by a taxpayer. However there is a CRA administrative position which states that they will not seek to tax miles/points personally accrued by an employee unless:

• The points are converted to cash.
• The plan or arrangement between you and the employee seems to be a form of additional remuneration.
• The plan or arrangement is a form of tax avoidance.

In those cases the employee is required to self-report the value of the benefit on their tax return.

If the points go into a corporate account and redeemed for the personal benefit of an employee, the company must report the value of the benefit on the T4.