I would prefer that when creating a new member in AGO, with Credit Allocation enabled, that the credit allocation for the new member defaults to 0 or 1 rather than defaulting to the total # of credits available in the subscription.
When credit allocation defaults to the total # of credits available in the subscription, there is a risk to the organization that a single user could burn up all the credits by performing actions like geocoding, or publishing tile services from ArcMap. When credit allocation is enabled, its often very easy to forget to update the default value assigned when a new user is created. It would be less risky to the organization if the default was set to 0 or 1.
Note that when credit allocation is set to 0 the user may not see all AGO functionality (i.e. the publish button in an item's details disappears).