Originally Posted by BayAArea

A discarded receipt that happens to match exactly the name on my photo identification and contains a destination that matches my original destination?

With a passenger receipt and a boarding pass that was issued but wont scan, we're into "we understand the intention here, there is glitch somewhere between the airlines interfacing that is preventing a smooth transition here. What do we do?"

I feel like there are two options now: 1) you play the hardball card like UA did and put your palms up and throw blame at the other party, or 2) if there is a way to override and get the customer to their destination which is point of airlines coming to work every day, you do that and work it out behind the scenes because you will at least have a happy customer that will come back again. These inter-airline transfers happen every day, for UA to sit there and act like AA wouldn't pick up the phone a few hours later (or they couldn't walk down the hallway to T5) to figure it out seems pretty implausible to me.

The last thing a customer wants to be told (especially at 1AM after traveling across the continent) is "sir, you did absolutely nothing wrong here but I am denying you the service". I will never forget literally sitting on the curb outside LAX at 1AM and dialing individual hotel chains trying to find a bed for a few hours, as a result of some airline interface or lazy gate agent. That is where you get customers with long memories that will swear off an airline forever, if it turns out it could have been accommodated.