I am local - so not staying at a hotel, but registered for DO and in fact coming early enough to volunteer at the desk. Can someone like this purchase the breakfast separately?

Normally I'd assume anybody can at least go to their restaurant even if not to the DO buffet, but if the hotel is 100% sold out for this event, I am not sure if the restaurant would function normally.

I can easily make alternative arrangements if necessary, just want to be sure.