They should all write letters to Chapters, pointing out that as long as US publishers continue to price books in Canada as though the exchange rate was still what it was six years ago, there's precious little reason to buy books from a Canadian bricks and mortar store. Buying direct from the US in US dollars is _much_ cheaper.
Although....
If Canadians buy 10% of the books sold in Nearctica and are paying 1.25x US prices (once the actual exchange is taken into account), Canadian readers are disproportionately profitable to someone between the publisher and the bookseller [1]. A US sale of a $7 US book probably includes the publisher getting about $2.80, the distributor about $1.40 and the bookseller about %2.80 (I think). If you sell that book in Canada, the price probably works out to about $10.00 US. I wonder who gets that extra $3?
1: Say, are royalties to the authors based on the US price only?