The additional cellphone capacity may not be enough to prevent congestion. A Verizon spokesman told the Washington Post:
"You can add hundreds of thousands of lanes to a highway, but if millions of people go for a drive at same time, you can still have a jam," said John Johnson, a spokesman for Verizon Wireless. "There are just so many unknowns."
Although cellphone service might be interrupted or spotty for attendees, emergency responders and 911 calls should not be adversely affected, as they will have priority use of bandwidth.