The Seattle No, is a passive way of declining something. Indigenous people of Seattle do not like turning down friends of acquaintances, therefore they passively decline without actually declining.
If you invite someone from Seattle to an event and they respond, “Hmm yeah that sounds interesting, I’ll have to check,” that is the Seattle NO. If they say “Maybe” and then you don’t hear from them for a while, that's a Seattle NO. If they say “I don’t know” in Seattle that means NO.
by Indigenous PNW'er February 06, 2014