That's what I had originally, yes. It doesn't work.
It doesn't show the validation message below the field, no, but it is validating because it redirects to the same page but with the querystring appended as specified:
$WAFV_Redirect = "add_news.php?anewsval=1&dID=".((isset($_POST["dID"]))?$_POST["dID"]:"") ."";
I have other pages on this same site that create and use session variables.
Got me well and truly stumped this.