Washington retailers have accepted Canadian currency for years. However I disagree with calling pesos legal tender. If a retailer likes to take it fine.....but to consider it legal tender is wrong.
True
A Canadian $ is worth what the vendor /retailer will accept it for, Pesos fluctuate more and best guess at point of sale may benefit the vendor or the buyer... a deal is a deal
Commerce should be regulated by those that engage in it.
TT