I imagine that, if they do this, it's because too many people were stiffing the delivery driver. Tip the driver like you would tip a waiter -- more, if the weather is bad -- and this sort of thing needn't happen. If they're doing this with take-out orders, I'd object too.
On grubbub there is a delivery change but that's not a tip. You can add a tip online when you're placing the order
Never ordered delivery, but take out orders a couple of times. No extra charge on take out.
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