I'm PRO-actively boycotting France. I filled out a comment card from my local Safeway about them buying French products and NOT supporting our troops. So far I've gotten three calls (messages)from their customer satisfaction group...
Business takes notice with your one card because they know there are probably 10,000 others who think just like you, but who didn't bother to fill a comment card out. A handful of such cards carries a lot of weight.