this. Also, from posts I've read, they do see the tip before accepting the order, and many drivers won't accept orders with low tips.
I stopped using this crap when I realized how stupid expensive it was, and I never tipped in the app, only cash in hand after delivery. Idk if they spit in my food, but a tip is for AFTER service, so you know how good it was.
And the driver only controls the SPEED of delivery.
Look at age old pizza delivery model. People liked that model.