It's not just the messages they cause to appear, but those they prevent from appearing: Every fossil fuel station ought to have a warning label that informs the user of climate change harms. The icebergs are melting and the reefs are dying. Photographs of these impacts should also be presented and required by law, just as they are in more effective tobacco cessation campaigns.

We won't be seeing these sort of labels in Seattle or elsewhere in the USA because of the ferocity which the American Petroleum Institute and other industry groups will litigate their morally indefensible activities.