Taco bell has done the same thing.
They'll send you free Dr. Pepper.
Pepsi did this a while back. They said that if Guns N' Roses, I think, released another album, they'd give everybody in the world a free Dr. Pepper. Well, they released an album. You had to go online to register for your free soda though.
So many people went on that the site crashed for the only day it was scheduled to be up and they never fixed it. There were some lawsuits about this, I think.