Put up a sticker and you've done your bit

Here.

Excerpt:

I HAVE this visceral dislike of bumper-sticker moralisers. These are people who go out of their way to advertise what they take to be their own exalted moral sensibilities, but do so at no cost to themselves and without the messy business of having to weigh costs and benefits or to choose between stark alternatives where none is particularly pleasant or easy. It's all form and no substance for these people, and there's no shortage of them around.