Though I don't know the specific case, if I'm in a public place wandering the Tideflats snapping photos of the wonderful grit I can do so. It's legal. A local photog over at Flickr was even hassled by a rent-a-cop about taking photos from Thea's Park of the a grain ship loading.
This all sounds like a job for the Tacoma Photo Gang to get the word out to local agencies that taking photos doesn't make us terrorists. Let's not have Tacoma give in to this kind of paranoia.
You ever feel like someone might perceive you as a terrorist threat when snapping pics around town? I know I do.