After these lucky pedestrians were informed that they had won, they still had to earn their prize. The winners had to bust their new WP7 device out of a solid block of ice, by whatever means necessary. You have to respect the marketing genius. What makes people stop and stare better than someone being violent?
On a practical note, we hope that the frozen devices were just dummy models, and that the winners got their phones in regular packaging. We also have to point out that this contest wouldn't have worked in other countries, where some customers are on CDMA networks. We suppose a CDMA-bound customer could easily gift or sell their device, but where's the fun in that?