Previously, internet users who were checking out as guests could only choose Eticket shipment mode.
With the newly introduced parameter "config.deliveryModes.guestCheckoutEnabled=true" at "Point Of Sales > Internet theme > Tab Advanced":
Internet users checking out as guests can enter a postal address and, therefore, select a postal shipment mode.
Due to privacy laws, internet users checking out as guests must enter their address for each new order. Indeed, the address entered may only be used in the context of a specific order. It can't be considered as permanent contact data.