This question was answered on our Q & A Wednesday show on June 14, 2017.
On most cruise ships, you do not have to pre-book entertainment. Onboard the newest vessels from Norwegian Cruise Line and Royal Caribbean you can pre-book shows online before you arrive. Pre-booking guarantees you a spot for the show you want to see, but it does not allow you to select a viewing location. If you want to get that front row center seat, you’ll still need to show up at the location in advance. On ships where you have assigned dining times or make reservations, make sure that you plan the show times around your dining schedule.