Stronger statement about potential problem with tying form creation to component rendering

apps/parent-form/README.md

@@ -78,6 +78,6 @@ Calling `this.parent.addControl(....)` is what ensures that the controls created
 
 ## Cons
 
-- The creation of the form controls is tightly coupled with the templates
+- The creation of the form controls is tightly coupled with the templates, to the point that if a child component is not rendered for some reason, the form controls won't exist either.
 - Since each child component encapsulates its form controls, the overall shape of the form data is not always clear