For me, they have worked better than not having them at all. Received golf clubs very quickly in PHX. Anything they try to do to help speed all baggage, from plane to terminal, is appreciated. I saw them load last an entire cart of P-tagged luggage on an MD80. Assuming LIFO (last in - first out) that worked out the way it was supposed to and p-tagged luggage came first on the belt on arrival.