Agreed that in all cases Doordash damages the restaurant, but in your first case, and in my example, Doordash is damaged even more (the restaurant will have to eat the loss in the short-term, but they have a VC-backed company they can sue for order-and-run+damages, perhaps in a class-action, if they don't get paid). After a platform-driven screw-up or two, it is hard to see a customer using Doordash ever again.

Your second example, however, damages primarily the restaurant, as the customer has attempted to disintermediate Doordash, but is doing so with incorrect information. The restaurant's best defense here may be communication, informing the buyer of the price, and correcting misconceptions, at the time of ordering.

As quipped eloquently in another thread here, "Move fast and break other people's things" may work in the short term, but lawsuits and grumpy attorneys-general seem like they could catch up to a bad actor pretty quickly when there is real money on the line.