[bradizbad]

Bidding is fine and will drop process and balance out long term, but seeing the tip before delivery creates the bad incentives described in other comments i.e. canceling an accepted order for another with a higher tip or not following instructions. I know I've been peeved after waiting 30 minutes only to find out my food isn't coming.

[jrockway]

That makes sense. The problem sounds like that some vendors let the delivery be cancelled mid-way through the delivery process, rather than making people commit to making a delivery that they have accepted. I'd think if we were serious about bidding to discover the price, there would be a queue of open orders, and then someone would accept, and they would absolutely have to do the delivery or be banned or whatever. For the customer, your order would either sit in the queue forever, or be accepted and you'd be guaranteed to receive your order. (This is challenging in practice because there are two concurrent processes going on; preparing your food, and then delivering it. You want to get the delivery driver en route to the restaurant so they show up right when the food is first ready; waiting on either end is lost money. The food delivery provider is walking a fine line where they'll have to pay for food that's prepared and thrown away if no driver is willing to transport it. And, I'm sure restaurants will want in on this price discovery mechanism, making it too complicated and unreliable for any consumer to actually use.)