@stloyd do you know what's the aim of the `isFresh` method of `CartEvent`? https://github.com/Sylius/Sylius/blob/master/src/Sylius/Bundle/CartBundle/Event/CartEvent.php#L63

If I refresh the cart directly in the constructor, we should assume that every listener has a fresh cart in its hands. And if it changes something, it's its responsibility to refresh the cart. What do you think?