Originally Posted by
Absolute
No, the "matrons" did the right thing, as the bypass is indeed for AC passengers only. It's always been that way - I don't think it's ever been opened up to UA before. I've had the same experience, on a UA arriving flight - and I've also been on the other side, back when I was an AC SE, before I switched to UA.
AC is footing the bill, which is why they have it for their passengers only. Although you may have only had a carry-on, AC is also the only airline at YYZ which will automatically transfer your checked bags to your onward domestic or INT'l flight - all other airlines must clear immigration, and then pick up your bag at the belt, clear customs, and drop it off before you re-enter the domestic terminal through a security check point. I believe it was back in '15 when AC started this process, for automated baggage transfer.
AC may have invested with GTAA and other airports for it to implement the changes necessary, but it is not exclusive to them, it is simply the rules set out by CBSA.
The ITD process requires that the domestic service be either operated by the same carrier as the international service, or the international carrier has to make an agreement with the domestic carrier. UA in this case would have to make an agreement in AC including implementing the necessary changes for baggage transfer. So if this is important to you, complain to UA.