justhere

I think for the most part all airlines can see the inventory for just about any other airline but that's not the point. I also think you are putting too much faith into the word "codeshare", at least in your situation.

The codeshare is still operated by a completely separate airline. Operated by being the key words. I can't think of a time where one airline has rebooked me on another, codeshare or not, and they haven't had to call the operating airline to confirm the seat. Granted I probably haven't had as many rebookings as many people here but I've had my fair share and they always call the operating airline. Even though the operating airline shows inventory for sale, that doesn't mean they will accept a rebooking. The inventory that's showing may be the operating airlines willingness to overbook their own inventory and therefore they most likely will not accept a rebooking that could cause a denied boarding situation for someone.

Also, I think most times that I've been rebooked on another airline, they either weren't in the same alliance (which is what I prefer ) or the few times they were, it wasn't a codeshare. The codeshare really doesn't have a lot to do with it IME.