I don't participate in things like this, as I don't like being forced to participate. I had a guy get angry with me one time, as he told me he was starting a pay-it-forward, and I told him thanks but no thanks.
A friend had a sour experience at a Starbucks. He got sucked into it ... expecting to pay $2 to $5 USD, the person behind him had an order for her office, $28 ... he was not pleased.