I think it's just a matter of time before Chinese forgers can make excellent examples of older Canadian notes, especially for some higher end notes. Eventually, they will figure out the paper composition of older notes, the ink colours, and the paper processing, etc... there are a lot of professional artists, etc. For example, I am sure there are other people like J.S.G Boggs in China:
http://en.wikipedia.org/wiki/J._S._G._BoggsMoney drives this type of business. I was watching a National Geographic Documentary, "Faking China". One show talked about counterfeit antique porcelain where forgers were able to deceive even porcelain experts from Sotheby's and Christie's auction houses. These forgers were able to use carbon testing analysis, exact composition of the clay materials in the porcelain, old dye staining methods, and then, used x-ray to change the carbon dating... (just like PD was talking about.)
For older Canadian coins with high value, there are some fakes on eBay, and some get caught, other's end up in collections where the "average" collector does not know they have a fake in their possession, it's buyer beware. Anyhow, forger and counterfeiters will learn from these mistakes and will continue to strive to make the perfect fake!