No. After the person shouted out "Verizon," Steve Jobs said they're using wi-fi so that doesn't make a difference. When you think about it why would Steve Jobs use 3G (an inherently much slower connection than Wi-Fi) to show off the speed of the iPhone 4? Like all previous iPhone demos this one was done over WI-Fi.
Obviously for future shows, a better Wi-Fi solution is going to have to found either by Apple or the hosting convention center.