Yea Boomer, the old grouch is back...
Busman, You are the one that mentioned RTW travel and SE Asia, since you claim to be a well seasoned traveler, and Cambodia/Laos (and Thailand/Cambodia)border is probably as infamous as any for exchange rates not in the tourist favor, you should be well aware of that issue.
The US Dollar is the defacto currency, bottom-line, not the lowly Canadian Dollar, which is rarely listed on the top 5 currencies of any window in a airport exchanging money, well behind the Euro, Pounds, RMB, Yen etc etc...
Give it up.