Here is what I did to get this to work property.  In my base page, i overrode the OnInit Function

protected override void OnInit(EventArgs e)
        {            
            if (CurrentPage.ParentLink ==PageReference.WasteBasket)
            {               
Response.Redirect("~/404.aspx");
            }
            base.OnInit(e);
        }    

Not sure if it is the best method but it works for our system.

You could do this as a PagePlugin too, if you don't have a base page.