Actually, in a 24 hour period, there is NO restriction on the number of times one can dine [excluding Caesars and Rio Seafood--unless you paid the supplement.]
I didn't suggest that there was a limit. Just that most people eat 3 meals per day, so if you buy a pass at 12:30pm, you can eat lunch, dinner, breakfast and a slightly earlier lunch the following day. Of course someone could eat 10 meals in that time if they wanted to.
BTW ranles, according to the
website, the Rio buffet opens at 11am weekdays, so this plan might not actually work if you stick to the Rio. I could have sworn they opened at 8am for breakfast, but I might be thinking of the weekend.
Anyway, the 24-hour pass is good at most of the other Caesar's properties (see details
here) so you can pop over to one of the others for breakfast if you want to. Rio has a free shuttle to Harrah's that is definitely open for breakfast at 7am.