Originally Posted by
blackllotus
AFAIK, the only cases where a segment will not earn mileage is for certain *A flights in deep discount fare buckets.
In the past there have been deep discount business fares that did not earn.
While corner cases and only a small number, you need to also list blind purchased tickets, BULK tickets, some consolidator tickets, some unpublished fares, ....
And of course award tickets, employee tickets, industry tickets, ....