I don't know how I feel about this realistically speaking the fridge door being open is more there fault then hers for using a normal fridge instead of one made for restaurants(like has anyone seen a door in a store/restaurant that doesn't close it self), but also quitting after one mistake and being forgiven for it is so immature its painful.
They're just high school kids, also if we're going to put in real world logic she should have took her aside to coach her on the correct procedure not in front of her peers. Praise in open, coach individually.
For a family restaurant a regular fridge would probably be cheaper and use less electricity, simply changing the leveling could make it easier, though not foolproof