really depends on when & where you want to go...we're just back - and last week was really slow/low crowds time almost everywhere. Most of the restaurants we ate at had tables available for walk-up. We had Boma breakfast reservations for last Friday (9/11)...did not need them. Had originally reserved for 8:00, then decided a later time would work better for us so changed to 9:00 about 10 days out. When I was trying to decide what time, I checked several different times...had my choice for a party of 4 for just about any time between 8 & 10:00 a.m. When we actually got there last Friday, it was very empty. Don't think they had even a 1/3 of the tables in use while we were there. Never anyone waiting at the buffet, either.
Now it wouldn't hurt to go online & get some reservations...but if they are available now on such short notice chances are there will be plenty of availability.