I think y'all are missing the point of the question.
Arlington, TX isn't Dallas either, but it IS a part of the Dallas/Fort Worth Metro area and BOTH are still in the same state of Texas.
Likewise, The Redskins play in FedX Field, which is in an UNINCORPORATED part of Prince George's County - which, coincidentally, is what Washington - the District of Columbia - was carved out of.
It carries a postal code designating it as Landover, Maryland.
Apparently someone is confused about WHICH "Washington" is a part of the Redskins team name, but I assure you it is not Washington STATE, where the Seattle Sea Pigeons play.
Detroit Lions, formerly in Pontiac Michigan, STILL at least played in the same state as Detroit.
Located in Oakland County - which is composed of 61 cities, townships and villages - it is part of the Detroit-Warren-Dearborn, MI Metropolitan Statistical Area & considered to be in the Metro Detroit area.
The city of Detroit is located in neighboring Wayne County, south of 8 Mile Road.
Much like Arlington, TX, where the Cowgyrls play, the city name where the actual stadium is located becomes irrelevant when the area itself is a part of the designated metro area of that team's namesake.
The Pistons playing in Auburn Hills are in the exact same boat, since Auburn Hills is actually on Pontiac's borders to the east and north.
It COULD be argued that The Meadowlands are a part of the NYC metro area, except that for all but statistical purposes it is part and parcel of the NEW JERSEY tax and governance structure.
Ergo, comparisons to Pontiac/Auburn Hills, Landover, and Arlington do not apply.
The Packers playing in Milwaukee is also irrelevant, since they never LEFT Green Bay since their inception.
That was a really poorly thought out counter-argument.