I've just seen that in a speedrun: If you collect enough moons to move on to the next world, and cash them in at the ship, the broodal ship just leaves.
Does that mean that the Broodal fight wont happen, so you missed the triple moon it gives? Or if you go to the arena, even without the ship you will have the fight happen?
Clip where this happens : https://go.twitch.tv/videos/200296642?t=11m45s