May be old intel . . . this is from a November 2021 cruise. But we booked an excursion, later changed our minds, and couldn't cancel online. We cancelled as soon as we got on the ship at guest services. It took them forever (like 25m) to reach the appropriate people handling the excursion, but they did in-fact ultimately cancel it. Full refund, no penalties.
We also had another excursion the next night (on board drink tasting) where it was just us and one other couple. The crew member told us everybody cancelled at the last minute, so it works both ways I guess!
- Jim