I don't think that Polymer notes are going to stop counterfeiting. It stop the guy who prints banknotes on him printer at home but the professionals are still going to make counterfeit polymer banknotes. There are many places in the world where if you have enough start up capital you can print money, make subway tokens, coins.
It might even be easier to pass these notes because the BOC is promoting how safe these notes are.
I believe that the BOC needs to do a few things to eliminate or reduce counterfeiting.
1. They need to make all notes prior to the current series in circulation non-redeemable except at the BOC after a certain period of time. This will eliminate older series being counterfeited.
2. They need to educate people better on the security features of our currency. Everyone should check their money. 99% of the people don't check their money. It is quite easy to pass a fake to a cashier and have it passed back to another customer.
When I was in South America everyone checks their bills both the cashier and the customer and they check for 3 or 4 of the different security features. Damaged or repaired bills are not accepted. This includes US and local currency. Some of the bills even have small stamps on the back indicating that they were check by a bank.
Counterfeit polymer bills have already shown up in New Zealand and they are almost as good as the real thing.
http://www.stuff.co.nz/auckland/local-news/rodney-times/4346908/Counterfeit-money-does-the-rounds