My friend claimed he ate 3500 grams of carbs after weigh in within 24 hours. He also didn't want to drink so he said his mouth was bleeding and by the end he couldn't even open his mouth or speak 
I mean if you are extremely depleted walking into a show and carry a huge amount of muscle, it is conceivable it will mostly fill you up rather than spill over. 3500g sounds very excessive though, it is what? 16,000 calories in carbs alone? Guy must have been a veritable shitting and farting machine.
Bri did not diet for his show and carb loaded anyway because he is a born pig.