You will need to guarantee your reservation with a credit card. If you fail to show up without cancelling the day prior, you will be charged $10 per person.
Thanks!
(Went online at 7am at 180 days and all times for the entire week were gone? Called the ADR line and they said it was possible that those date were not open for reservations yet, guess I'll keep trying).
Good luck, we just stumbled onto the Tea Room when we were exploring the Grand Floridian. We tried a walk up, but they were out of seats. They strongly recommended reservations, but I believe they have a few seats that are first come first served.