How can I prevent users from removing a parent node with child nodes in EDMCS?

Summary:

I'm trying to implement a custom validation in EDMCS to prevent users from removing a parent node when child nodes still exist beneath it.

I created a custom validation on the Hierarchy Set with Validation Scope = Node, Trigger Action = Remove, but the validation does not appear to be evaluated when the node is removed.

Content (please ensure you mask any confidential information):

My requirement is:

• Allow removal of leaf nodes.
• Prevent removal of parent nodes that have one or more descendants.
• Display an error message instructing the user to remove or re-parent the child nodes first.

Are there any limitations with custom validations for Remove actions that would prevent checking whether the node being removed has children?