I worked right next to one of the pilot stores when Subway started order online about 12 years ago. It worked pretty well. About 10% of the people used it and

I worked right next to one of the pilot stores when Subway started order online about 12 years ago. It worked pretty well. About 10% of the people used it and since everything was made & paid it took a few seconds to walk up and get your order. The trick is getting the employees to encourage the behavior. The Subway workers would shout every few minutes things like "People that ordered online please come to the front" so that everyone else knew what was going on and people didn't feel to embarrassed for cutting in line.