My first, best, favorite, and only Seattle friend Sean reached out to me yesterday with this fine gem. I actually recall this meta-incident happening about 3 months ago, when he posted his account of it on facebook.
I've enlarged it for your viewing pleasure (you can see it better if you click on it though):
Basically, it's really sketchy to see a ton of huge bags being moved out of your neighbor's apartment (unless they are actually moving and have a moving truck). It's probably even creepier to find out that it's just bags full of bags, because what was your neighbor doing with hundreds of plastic bags anyways? Apparently, not reusing them.