Originally Posted by sydneyracquelle

I am from YYZ. There are 3 completely different areas. Domestic within Canada, pre-clear USA and international. You have to recheck your bag in the preclear-USA area in case US Customs wants to check it (you and your luggage will both arrive in DTW as if it was a domestic flight). The YYZ employee misdirected you as if you were flying internationally and not to USA.