When you share a Feature Service with another non-admin creator user (view access) this user can use the ArcGIS Python API to clone this Feature Service, either within the same organization or potentially to a different ArcGIS Online organization if this user has access there. Ideally, you want to differentiate the functionality of sharing data with view access to another user from granting another user the possibility to copy the data to a new item and do as the user pleases with the data. The user can decide to share the data with other groups, the full organization or share it publicly which perhaps wasn't allowed in the first place because the data is confidential.
It would be helpful and more secure if you were able to limit this functionality without taking away the option for your creator users to use Notebooks entirely. I could imagine this could be a setting in a Feature Service where you disable the functionality to allow other users to clone it to a new item and share it independently.
