What happens when I check a bag that goes across two carriers, AC and carrier X or carrier X and then AC? Who is liable for any damage? How are you going to figure out who damaged it?

Also, if this becomes an expensive issue for AC, I can see them taking extra time during checkin to look at my bag. Pictures perhaps? So much for all that self bag check AC has done to speed the process up.

Why does anyone buy expensive luggage when you know it is going to get damaged? Just look at the belts the bags come out on. You've seen bags get stuck on the belt, a zipper gets stuck, two bags jammed together, the strap catches on something, bag falls off the belt etc. I'm not saying you have to have a bag that looks like hobo luggage but don't expect a checked bag to go through the flight process without some nicks and scrapes.