Toledo is on the border of Michigan. Canada is a good 60 miles north of us. Anyway, we didn't get CBC over the air. CBC was carried on our local cable system. Apparently, our cable system made the choice to carry CBC Channel 9. I can't remember if the over the air signal out of Windsor was strong enough to pick up in Toledo. I'm sure Detroit and Windsor had the on-air carry over you referred to. In fact, when I was in grade school, the most popular radio station around was 800 AM CKLW out of Windsor. It was what us radio people call a "flamethrower." Its signal was so strong that it was clear as a bell throughout most of Ohio. Even though it broadcast out of Canada, CKLW was positioned as a Detroit station at the time. It was the undisputed champion of Top 40 radio. Today, it's a full on Canadian talk station and I'm pretty sure the signal was either turned down or redirected towards Canada because we can barely pick it up these days.
EDIT: Speaking of flamethrower radio stations. Last week, I was listening to WTAM 1100 out of Cleveland - while I was driving in Spring Hill, FL which is 1060 miles from Cleveland. 50,000 watts and a clear channel will do some distance on AM radio.