Two instances to tell you about:

1- my IAH-SLC flights got me miles and bonus too on both trips.

2- I flew IAH-EWR-DUB RT and it was a buy 1 get 1 free deal on Bestfares. Well the paid ticket got the miles and none for the free ticket. To my horror my fiancee's ticket was paid. (I'm OP GOLD) But when I called after I got back, CO allowed me to get the miles and bonus but debited her account. Almost lost 100% bonus for the trip.

I think doc is right, you never know.