Does Fusion secure the supplier bank account for internal users by BUs?

Summary:

We are a big instance used by many BU internal financial users that they are in separate operation. And supplier profile change request approval is not enabled.

How does Fusion handle the 2 scenarios of the supplier bank account shared across same supplier and different suppliers.

1. Same Supplier with different sites belonging to different BU.
   1. User A has access to supplier site A of BU A of Supplier A only. User A creates a supplier bank account attached to the supplier site A of BU A of Supplier A.
   2. User B has access to another supplier site B of BU B of Supplier A only. He then uses