Why doesn't YYZ recognize international conventions for handling duty-free in bonded bags? Why doesn't AC let me check a carry-on for free if that's the only way I can bring duty-free alcohol with me from the US to YYZ and then on a connecting flight within Canada?

Why aren't more people complaining about this? How many more years is this going to happen?

If I have no checked bags, why can't I stay on the air-side to get to my connecting flight after I pass immigration on the upper level - without going down to the carousel level - and hence keep my duty-free with me?