I agree that it seems inappropriate to preserve order. That seems an inappropriate imposition, inconsistent with what SQL does elsewhere.
If there is a natural sequence (e.g. - a value assigned by nextval()), that offers a natural place to apply the usual order-imposing ORDER BY that we are expected to use elsewhere. I suppose it is troublesome if there is no such natural sequence, but I wouldn't think it too meaningful to expect order without some visible source of order.
