I agree, but the move over , ever increasing inducement takes time, this seems last minute, but given right wording shouldn't take more than a few days if inducement was enough.
But nothing stopping Cunard emailing everyone with balcony, offering healthy inducement and asking for volunteers. I'm sure if they emailed what must be hundreds, they would get enough willing to have a refund and OBC. This would be easier for those they can email to directly not via TA.