Burlington, VT and Manchester, NH both have this. Merchants usually display these prominently on-site and in their advertising.
In Burlington, Ben and Jerry received one of these while still just two bohemians working out of a 'barely renovated' former gas station - I worked at the restaurant that existed right next door (Carbur's). Now the restaurant is closed, the gas station is gone, the plaque that marked the gas station location is stolen...lets see, what was the question?