Last December I was a "no-show" due to a storm that grounded planes at a connecting airport. (The grounding happened too late to cancel the reservation in time to avoid "no-show" charge, although I did call in and tell them I wouldn't make it.)

I received full double-double credit for that one. (Don't know whether that was policy, or just something nice because it wasn't my fault I was a "no-show", but either way I appreciate it.)