It would probably be abused all the time and the claims would be for larger amounts than the difference between two similar plane tickets. There would be people claiming they had to buy a car for $2,000 more just because they missed some kind of window where the price was cheaper (even though that doesn't make sense). I don't think any bank would open themselves up to that kind of liability. Even if they would, I think they'd cap it to a low amount that was close to the cost of eating chargebacks.