Entering Canada with prior misdemeanor adjudication witihhel

I just checked the Canada Law and their drinking age is 19 in every province I found. The person she sold to was a police academy recruit at the academy I used to teach at years ago. So i wonder if the fact that the person was legal age to drink in Canada would make a difference? Been trying to find a phone number to call Canada but have had no success in that regard at all.