Last April my wife and I were traveling on Continental Business class reward tickets to Europe, and were downgraded to coach on a IAH-EWR segment due to a change in aircraft. (A domestic DC-10 with 18 F/C seats was substituted for a DC-10 with 38 Biz-first seats.) We were told at the gate that since we were traveling on "free" tickets they could not put a value on them and offered us either $100. or an upgrade certificate for a future flight. I declined the offer, and on arrival at Newark called the OnePass Service Center to request more reasonable compensation.

We were quickly offered 20,000 OnePass miles each for the inconvenience, an offer that I thought was reasonable and appropriate under the circumstances.

A note about the flight:
I don't think that the passengers in coach appreciated having share their cabin with 20 grumpy people who thought that they were going to be traveling in F/C. A flight attendant said that of the 20, 15 were Platinum Elites. An announcement was made that they were offering complemtary headsets for the movie, and I noticed that during the flight that no money was exchanged for alcoholic bevrerages. (No anouncement was made about the free booze!)