This is interesting. I was in a store the other day, and asked if they had received any old notes lately. They told me they don't accept anything before the journey series due to counterfeiting. She told me specially the five dollar birds, because they don't have the security foil. Very strange I thought, the five would be the least counterfeited.
I know some places don't take the larger denominations due to counterfeiting, but I don't think this is as big of a worry for the new polymer notes? At least, not that I am hearing from the general public.