I thought about this last night when I saw the story. No, I wouldn't have participated — I'm another of those folks who gives back extra change. And, as one of your commenters said:

if I were the gas station owner, it'd still come as an unwelcome shock that my neighbors were all willing to do this to me. And I'd want to know who, so that I would know not to trust them further than I could throw them in the future.