A system needs to be set up to prevent order theft. Uber has something similar with their driver app. They force you to submit a fresh on-demand photo of yourself before you can use the app. The same thing can be done in DoorDash. A Dasher can take a picture of the person that claims they made the order. DoorDash can automatically compare that photo to the profile picture of the account holder. A green light can be issued to finish delivery if the two pictures match.