Its not an IT issue. Its policy. The policy is you can book shows in advance at some changing date on oasis class ships. If you get on day 1, you can book as many as you like. Day 2 they are all sold out. Now I realize there are more to book on board, but the guy who got on day 1, most likely booked every show he wanted. You are wrong about walking on, because we experienced the exact same thing on the last oasis cruise. At that time we didn't know to book as soon as you get on. By the time we looked they were all sold out again. We then did standby and were turned away at least half of the time. The ones we got into, the seats were awful.