Well, it used to be Emancipation Day, right? It was recognized - and with picnics - for as long as I can remember, in the form of peaceful picnics they'd hold in Windsor parks (Detroit just didn't have the kind of green space the Canadian side does, so organizers would rent space there.) Of course, this was way back when Windsor cops still had a height/weight requirement ....

It just wasn't made a huge big deal of otherwise, it'd get a mention on the local news and that was about it.