When you include an item in a collection or presentation, the item inherits permissions from the collection or presentation (permissions are cascading), with the following exceptions:
Inherited permissions do not override existing permissions on items. For example, if you give an individual the view, see comments from others, and add comments permissions for a specific item, but only the view permission is set for a collection that contains the item, the individual is able to see and add comments to the item. This is the case regardless of whether it is accessed from the collection or outside the collection.
When you associate a reflection with another item, the reflection does not inherit permissions from the item, nor does the item inherit permissions from the reflection.
Sharing a reflection associated with an item, only allows users to view the name of the associated item. However, sharing an item associated with a reflection allows users to view the reflection as part of the item.
Links:
[1] http://staging.docs.d2l/en/taxonomy/term/3