It was Delta but, instead of refunding those loyal members who were disadvantaged by the glitch, the company position was that if the FF was charged a higher price they can call Delta and ask for a refund under the 'lowest fare guaranteed' deal they have.
It was a Delta issue...The CNN report mentions that some Delta FF paid $100s to $1000s more. Blamed on a computer glitch. Delta doesn't plan on sharing this, but if their FFs have concerns, they can call to discuss. Heads up you Delta flyers.
Delta was very cagey...The CNN report is online.. search there website. The report came from a person working for CNN in Minneapolis, I think. I don't recall the details, but please check it out. I think the Prof is a big Delta flyer, also.