Not that it would necessarily help in the rest of the world, but I think such an issue would be ripe for a class action lawsuit in the US.* Just think of the McDonald's coffee spill case.

I'm talking about what really happened in that case, not everyone making fun of the situation because someone got a bunch of money for spilling coffee. The lady kindly asked McDonald's to pay her (few thousand dollars, iirc) medical bills, and McDonald's told her to go pound sand. When she took the case to court asking only for compensatory damages, the jury awarded punitive damages. A similar award could force a behavior change and at least end the deceptive practices. I would have no problem if DCC were really a conscious choice with all of the information clearly presented to the customer.

*Note: I am typically not in favor of these cases as they're usually a net loss for both parties.