To be honest, I think they're already exceeding that. I've only been affected by two cancelled flights; on one of those, they refunded me and on the other they rebooked me AND sent a $100 voucher. I was on a flight delayed > 3 hours before, and they automatically sent me a $25 voucher (on a $19 flight). I'd suspect they're already complying, though they may balk at providing a refund vs. a voucher.