mrex....
The key here is possession. Ontario rules for that water clearly say that if a fish is NOT returned immediately to the water, the person catching it is in possession of it and will be for that day even if the fish is given away or eaten or froze. The Ontario CO's found him in possession of a smaller trout earlier. The larger fish put him over the limit when he kept it.
I am not saying that I agree with the rule, but if you fish a particular water with specific rules, follow them. Its simple. If the rules are something people don't feel they can follow, fish somewhere else. Lac La Croix is a trophy water in large part due to its serious application of rules to limit harvest.