The stuff ya bought at the duty free is the Canadian version and it is over 12. The stuff ya bought at the party store in Michigan wasnt.

I grew up outside Detroit so from the time I hit 18 I was back and forth on many weekends. Beer, strip bars, casinos all with an 18 drinking age. Always hit up the duty free for some tax free beer with higher alcohol. Then I married a Canadian gal. Her family is in London area. Over 40 years hundreds of crossings between Detroit, Port Huron and the Soo. Last time was Christmas 2019. We havent seen the wifes family since.