What if the Occupy movement held a one day boycott?

I have seen articles talking about a May Day strike. I was thinking though of how effective a one day boycott would be symbolically. What I am thinking of is some well publicized random way of choosing a major company and product. It could be based on things like the last digit of the Dow Jones average or the last digit of the temperature in Washington D.C. on a certain day. As I see it, there would be no real damage caused to anyone, but it would send a strong message. Just think of all the company analysts pondering the one day blip in the monthly sales.