Hi
Case #3378972. Refer this for details.

When someone in our domain receives an invitation to collaborate in a folder and they don’t yet have a Box account, an account will be provisioned and that user will automatically become a managed user under your enterprise instance. This is some kind of a backdoor account creation which we want to have a control on. We have account approval process where Cost Center managers review and approve the license cost. Need this capability to have a control over this way of account creation.