Chase would likely give you a courtesy credit below a certain threshold automatically. A larger purchase like at a hotel or department store would likely result in a chargeback situation. I don't know at what point they'd say, "Enough is enough!" If they started getting a flood of complaints from people like us about getting hit with DCC, perhaps they'd take the case to Visa. I imagine that by the numbers Chase is one of the largest issuers of Visa cards in the world, so you would think they'd have some pull.

Furthermore, with Chase it's really easy to see exactly by how much you got ripped off with DCC. The posted transaction amount without DCC is the Visa rate on the posting date. So, you multiply the Visa rate on the transaction posting date with what the price was in local currency and subtract that total from the amount that shows up on your statement.