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.