Originally Posted by srodr
I learned long ago to avoid ever giving an account number unless it is definitely the one that you want credited. I fly Delta a lot and always credit it to my NW account (for the elite bonus) even though I have a Skymiles account that all my credit card points go into. So every Delta ticket I buy, I have to make sure that I am not signed into my Skymiles account, and then I have to remember to add my NW number later, either at check-in or by phone. Yes, it takes longer to enter all the information each time. But it is the only way to make sure that Delta doesn't screw up the miles.
I've been around the block a few times and have flown several million miles. I have never heard of "preferential" crediting before I booked this first (and possibly last) Delta ticket.
I've dealt with split points/status credit, I've given the wrong number before, but I've never had to specify where I did
not want the miles to go to, and I certainly have not ever had my BPs read correctly and the miles post somewhere completely different. I've had them not post at all, but that's a different story.