Yes they charge 3%
And my credit card also charges a 3% currency loading.
I have no idea how bad Chinese Law is in terms of consumer protection but under European jurisdiction this behaviour would cost the airline a fortune. I'm pretty confident that my UK credit card company will be liable for the difference.
Ultimately Ctrip as agent is earning a commission and has to take liability - when the real world arrives.
This was the e-mail explanation I got when asking for a formal communication for Insurance company purposes.
Withregard to your flight booking(order 680274937, Shanghai- Macau), the flight was cancelled by the airlines and they informed us you need to try at the airport to change to NX109 but they could not guarantee it. Ctrip is not responsible for any outstanding cost caused by flight change or cancellation. If you are willing to try to change flight at the airport, please inform us as soon as possible. We apologize for any inconvenience you have experienced.