Is there a legal requirement to tell your doctor you are a pilot? Specifically if I visit a doctor in Canada who is not a CAME for my regular aviation medical, do I have to tell him/her that I have a pilot's licence?

You can imagine why I'm asking.  I just explained to someone that I'm supposed to mention this to any doctor I see.  However, it's been ages since I've flown and I would no longer do this as I haven't even kept my medical up to date.  

I've just searched the CARS and can't find any reference to this being a law.  Is it possible I was told this by mistake, or as something that's just recommended?  I do recall doing this once or twice and the doctor didn't just pat me on the back and say "good for you".  He nodded and just acted like it was a normal thing to be told.

Not sure what tags are available, but I'm interested in answers from other countries as well.
In the US, you are not required to inform a doctor that you are a pilot. However, on the application for a medical certificate (Form 8500-8) you must list all "visits to health professionals" in the last three years, including type of professional and the reason for the visit.

The medical examiner uses that information to guide questions to ask about your medical history: a yearly checkup with your family doctor will not be remarked on, while a visit to a specialist might invite scrutiny about that area of your medical status. Depending on any existing conditions, you may need a letter from your primary doctor explaining your condition, but you would specifically ask for this rather than expect it to be provided.