When tied up to a mooring ball in this area (the Massasauga Provincial Park), payment is made to the Ontario Provincial Park's guys who come by in a small boat to collect the fees, as well as take away your garbage for you.
Sometimes, such as in this instance, nobody showed up when we were there, so we didn't have to pay. Not that that's an issue, because it's very reasonable, but sometimes they don't have enough time in the day to drop by every boat at every location. They will also collect a $10/night fee if your boat is tied to shore anywhere in the park. And that goes for all the boats who may be tied to shore together.
What I mean is that we have been there with four boats tied together (us and three friends) with a line running back to shore for stability. When the Park's guys came by, we all had to pay the $10/night. Again, we are good with that, because they will take the garbage away and best of all, tell you where the nicest anchorages are :-)
Have a look at this video I did from a trip there back in 2009. You'll see what I mean about the boats all tied to shore;