Domino's believes that "every great delivery driver deserves a tip." I guess that's why the pay for delivery drivers is so poor- Domino's expects the customers to help pay their salary. It didn't become a billion-dollar industry by paying its employees a decent wage, after all.
And why is Domino's willing to knock three bucks off your pizza if you pick it up yourself? Well, there's the cost of gasoline, for one thing: The boys on the board have crunched the numbers and figured out that if they want to keep providing delivery (not "free delivery"- that went out the window decades ago) they are going to have to mark up the price of their pizzas, which is going to reduce the size of their customer base (and reduce the size of their customers, too.) A much better solution is to cut back on the number of $10 per hour delivery guys they've got hauling boxes of warm bland carbs and sugar to tasteless twats in the 'burbs by offering $3 to those tasteless twats willing to pick up their own sludge tossed into cardboard which is only slightly less nutritious than the sludge itself.
Now I'm irritated that grocery stores don't offer a "tip" to customers using the self-checkout option. Why did so many people just gravitate to those scanners, where we have to do all the work, without one dime of incentive? Time for a consumer strike?