They tried this last year and I'm not sure it did anything. We don't have too many Exxon or Mobil stations in Tucson so I didn't have a hard time complying.
So I'll continue to not buy gas from Exxon/Mobil. If you do the math on their profits and all the other companies profits I think it adds up to approx. $1600 per U.S. driver per year. sickening