If the food delivery driver is knowingly not delivering any food, but is paying for the "food" anyway... that seems pretty close to fraud.
If you order a shitload of real food and the pricing works out well for the restaurant, it's weird but it is still following the rules that DoorDash set out.
But if Doordash never made an agreement with the restaurant in the first place, like in the article, the restaurant has no obligation to follow any of Doordash's rules.
That doesn't mean they won't fall afoul of some state or federal laws in doing that.
Nobody saw the episode of Bagpuss [1] where the mice just role out a cookie, and then take round the back of the "factory" and deliver it again? Apparently we've been waiting 46 years for this particular innovation to have a real world opportunity!
I can only assume that such a large order would be eventually flagged by the system. But I imagine ordering 50 pizzas every night can be relatively "normal"(feeding the night shift or whatever).