Prevent content-delete action if specified node is of non-content category

Currently, it is possible to specify a content action to delete (or reload) node /a/b/c (e.g.) if that node is not content, i.e. if it either exists in the ConfigurationModel or if its closest ancestor which is part of the ConfigurationModel specifies that its relevant child node has a category other than "content".
I guess (TBD) this should be prevented.