In a Data Model, once a Data Model object is deleted the child of that DMO does not get deleted but remains often.
In this case a validation message should be given to the user before deleting, informing the user that the child nodes would also get deleted.
Validation message: Are you sure you want to delete "<Asset/Device Name>".
You would also be deleting the "<Object 1>, <Object 2>, <Object 3> etc"