Yup, belM is right about the SS number (actually called social insurance number or SIN here - how funny - no one thinks twice about the acronym). After our discussion began, I checked it out on the gov't website. The only people you must give it to are the tax people, employers (to deal with tax and pension stuff), and banks (because you earn interest from them which counts as income). Some businesses do ask for it anyway, not knowing or not caring about the rules, but you don't have to give it. However, they can deny you the service in question - which is kind of contradictory - if you don't want to give them the number.
Anyway, most places do follow the rules, so like belM I have a different drivers' license number, medicare number, student number, etc., etc. Furthermore, I don't think that the DVL even has my SIN anywhere on record. They never asked for it when I got my license. The University has it because you get tax credits for tuition, but they don't use it as a student number.
