It's indeed actually a law that's been in place since July. I know a number of folks who have flown since the law came into place and they haven't had any trouble. They just show their letter.
If you want to get confirmation or make a complaint on this law, you can contact this person:
Sandra Miller
Chief Regulatory Planning and Services, Regulatory Affairs, Security
Transport Canada
330 Sparks Street, 13th Floor, Tower C
Ottawa, Ontario K1A 0N5
Telephone: 613-998-9605
Email:
sandra.miller@tc.gc.ca