Allison's restaurant, which has very similar customers to Sarah's, adds a third option: pizza only for $7.
As expected, none of her customers choose this 3rd option, since it is strictly worse than the combo. However, 30% of her customers order the hot dog, while 70% of her customers order the combo -- the exact opposite of Sarah's customers!
When faced with effectively the same two menu choices, the customers preferences completely reversed. Is this possible in real life?