I agree don't bother playing on the ship. My husband and I actually have played shuffleboard many times, but it was horrible on the ship.
We didn't encounter the kids problem, but the court on deck 4 is not a suitable shuffleboard court. Shuffleboard needs to be played on a smooth surface, and deck 4 definetely isn't smooth! We tried to play for a little bit, but gave up due to the nonslip surface.