This is an interesting analog of the problem retail workers have on shift scheduling and shift changes.

"One day Amazon dictates that you have thirty routes, the next day forty, then the day after twenty. You’re supposed to have enough drivers for back-up while Amazon is lowering pay. Amazon’s actions are unlawful."

Delivery is probably something you want to run in house and not outsource. It opens them up to another group that could push to unionization though which is probably why they went the Uber route.