The only implicit dependency is the interfaces. So when a node goes down, the interfaces are marked as unreachable and you'll only get a notification for the node going down. This is automatic. The rest of the dependencies you need to create.
If a node is a parent for other nodes and it goes down, the other nodes will be marked as unreachable (inc the interfaces) and you'll only get a notification for the parent.
I hope that answers your questions.
