So, I can't remember where I saw it but CO's were giving fines for not having the Outdoor Cards. I can't remember if this was resolved yet.
Early on people thought oh just carry the paper but then when stopped they did not have the card.
From the https://www.ontario.ca/page/get-outdoors-card
It stills states:
you must carry your Outdoors Card when hunting or fishing, unless you have just recently purchased the card and not yet received it in the mail. In this case, you must have a copy of your License Summary available.
An Outdoors Card is a plastic, wallet-sized identification card issued by the Ministry of Natural Resources and Forestry that allows you to hunt or fish. You are required to carry this card with you at all times while hunting or fishing.