I'm in the US, if these apps are going to depend on customers tipping for their drivers to get a reasonable wage, then tipping/delivery fee should be required. If people aren't willing to pay the drivers for their labor, they shouldn't place the order.
Won’t happen. It’s the perfect way to underpay people. You can overpromise and underdeliver without breaking the law. When your workers get upset about poor pay, they’ll mostly direct their ire at your customers rather than at you.
I would be happier to do it if there was transparency about how much of the delivery costs the restaurant is covering. Delivery services benefit both producers and consumers. I'm not willing to be on the hook for the whole thing.
If tipping is required it is no longer tipping. It’s a tax/fee.
I don’t get why people are expecting to receive tips even if the service provided is fine at best.