I have volunteered many a time for free vouchers but on a recent AA flight from SFO-JFK, I had upgraded using my electronic upgrade stickers when they announced a smaller plane would be substituted for the original one due to mechanical problems. I was called to the front desk and told that they didn't have as many seats in First Class and Business Class and needed to put me back in Coach but would give me $500 vouchers. I told them this was fine but should I have negotiated this?