Originally Posted by
cfischer
It's not a ST E+ benefit, but some airlines chose to give this to their Elite members. For example I get access to NW lounges on domestic itineraries, but nor CO/DL. Every airline has their own rules, also regarding contract lounges, which are in addition to published ST rules.
This is a published benefit of FB program. FB GE and PE passangers have access to NW clubs flying NW domestically; there is no such benefit when flying CO/DL for FB GE/PE or when flying NW for other ST E+ passangers (including NW own elites).