WSU alumni have teamed up and ship the banner to each other each week based on whoever is close to the upcoming Game Day. They’ve been trying to get media attention for their team ever since one year in the BCS days when they thought they had an outside chance of getting into the BCS championship game if only they could put themselves on the radar. This is back in the early naughts, maybe 2002 or 2003. Maybe this Saturday is the last Saturday we’ll see the banner. :) I doubt it, though. I think the Cougar banner at Game Day thing is its own tradition and will go on forever like a lot of college football traditions.
They’re also one of the fan bases that pushed the “We want Bama” meme years ago back when saying you wanted to play Alabama was synonymous to saying you thought you were good enough to play for the national championship. That’s what they all say. :) Many have tried, few have been successful (Ohio State in 2014, Clemson in 2016), and even then only temporarily (Clemson losing to Bama the next year in the playoffs).
Watching ‘Bama this year is like watching Patton rolling towards Bastogne.