somewhat OT, but just wanna add another data point for bump (voluntary) ex-North America, but in this case for Oasis ex-YVR. my parents were scheduled to travel J with them today (on senior special fares, HKD 4500 one-way only) - were asked at check-in whether they would like to give up their J seats, with two options:

(option 1) take Y seat today + a free one-way Y ticket for use in the future (I assume it's YVR-HKG) + 75% refund (i.e. ~HKD 3375)

(option 2) take J seat tomorrow + a free one-way Y ticket for use in the future + CAD 750 credit for use towards another J ticket in the future (I forgot to ask whether it's for one or two, I assume it's one, so two of them = CAD 750 x 2) + one night hotel + 3 meals paid

sounds like they're actually quite generous in terms of bump compensation compared to the USD 400 the OP received...esp given the one-way J special fare I paid was only HKD 4500 per person...