How is it against airline rules to receive credit for two airlines when rerouted. If I am flying UA and then rerouted to AA. I call UA and ask for the miles, they are fully aware that I will automatically receive the miles on AA. When they agree to credit you the miles, I highly doubt that they think you will call up AA and tell them you don't deserve the miles. I am sure that UA realizes that I will be receiving miles from both programs for this flight, but are Ok with it since, i apid for UA miles.