I just learned this lesson myself earlier this month. We weren't at check in though and still had 3.5-4 months to go but all that was left was late with early and any time as a waitlist option. I've check any time for waitlist but when I save nothing reflects that we are waitlisted so quite confused. Plan to see about a change when we get on the ship in October but if they can't accommodate, I guess the wife and I will make the best of it. Harder to do when you have kids with you that is for sure. Only our second cruise and first was a wedding so all the dining was pre arranged for us.