I believe that Canada is treated the same as the USA as far as agencies go. In that case, if you are acting as a divemaster, then you need to be "current" with an agency and insured. That may be through an umbrella policy with your dive shop or as an individual, but if you are acting in that capacity you need to be insured and active with your agency, no different than an instructor, just cheaper.
I'm going to go out on a limb, albeit a sturdy one, and say that you're doing this with Dan's dive shop given your location and NAUI? If you are doing any shop sanctioned anything, you really need to stay current for the safety of that shop.
Being a NAUI member means you get to vote for the board of directors, but it's mainly if there was an issue in the water that you would have some semblance of defense.