At first I read this:

http://www.kelownadailycourier.ca/to...473&type=Local

Which says that if you travel on mountain roads in BC, you must have chains in your posession or winter tires, and that M&S (mud and snow) tires don't cut it.

And, just now, I've found this, which says that M&S tires are sufficient:

http://bc.rcmp.ca/ViewPage.action?si...12651&q=chains

Obviously (or perhaps naively?), I'm going to take the RCMP as more authoritative than the Kelowna Daily Courier, and not worry about it anymore. I think it would be hard to find a rental car in YYC with tires that don't have an M&S rating.

Thanks