Do not delete inline entities if they are referenced by other entities

Problem:

1. I have an entity reference field that can reference nodes.
2. I use the multiple value widget + ability to select existing + 'delete entity if parent is deleted' enabled
3. I create node A that adds a new inline node B
4. I create node C that references inline node B
5. I delete node A
6. Node C is now missing it's referenced entity :(

Expected results:
Only delete the referenced entity if it's not referenced by other entities aside from the parent entity.