Initially, having a policy of only refilling the establishment's growlers may have been based in the idea of increasing brand loyalty. But as soon as a couple of places broke away from that policy, most brewers realized it was better not to require the glass have been from their establishment
i always wondered if places would refill any growler. why not? you are paying for the beer. if you were really into growler beer, would you really have to have one from every brewery? maybe you could have a blank one