I'm no lawyer, but I do deal with contract-law quite frequently in my job. The Tariff and General Terms and Conditions are certainly PART of the contract and are the part specifically subject to CTA regulations, however, under common and other statutory law, they are not the full extent of the contract. Any promise, stipulation or inducement to enter into contract effectively becomes part of the contract - even a verbal contract is a lawful contract, it is just not easy to substantiate. Since AC publishes the Aeroplan points earned with the various fare classes when booking tickets on the AC webpage it would be no stretch to argue that these become part of the contract. For example, booking a domestic T+ ticket brings me to a place where I can read:

"Air Canada Status Miles 100% - Accumulate Air Canada Status Miles as indicated for travel within Canada and between Canada and the U.S., including Hawaii, on all scheduled flights operated by Air Canada, Air Canada Jazz™ as well as Air Canada codeshare flights operated by Air Creebec, Air Georgian Limited (doing business as Air Alliance®), Air Labrador, Calm Air, Central Mountain Air and Pacific Coastal. Aeroplan Miles earned for distance flown on Tango fares do not count towards Air Canada Top Tier status. For more details on mileage accumulation, visit aeroplan.com."

While it references "details - visit aeroplan.com", it doesn't say subject to terms & conditions at aeroplan.com. Regardless, the aeroplan t's&c's state that final authority for mileage earning for flights is the airline not AE.