It's always going to be a question of who's around that day. If you have friends in back, they might go the extra mile. With a place like McDonald's, going too far off the rails is going to disrupt the efficiency of the operation, and somebody is going to notice.
The one thing that annoys me is when there are smaller airport versions of fast food places that have limited menus. I can clearly see from other items on the menu that you have the ingredients and equipment to make most of the mull menu. Why not make everything that you can?