You have to ask, is the expense of getting to Canada and...

You have to ask, is the expense of getting to Canada and attending the event made in producing your assessable income? Maaaaaaaaaaybe if your main source of income was divideds, or if you were carrying on a business where obtaining dividends was its main source of income, then you could write off an expense that somehow gets you more divideds. But seeing as dividends themselves are not a guaranted source of income, that is already a stretch.

Same goes for selling your shares, however that would be easier to draw a nexus between having a business that trades shares in mag stocks and then writing off your trip to canada as a deduction.

Anyways, not a lawyer. Just a law student about to finish a Tax law course (and hopfully pass)