Have you been to an SEC stadium for a football game? No special technology is required to jam the cell phones. The extreme concentration of people with phones usually overwhelms the capacity of the cell networks. The real danger from the conference's perspective is the home viewer tweeting details of each play. Most of the cell activity at the game is people trying to coordinate with family and friends about locations and refreshments, game statistics, or scores from other games. Overall, the last thing the SEC needs to focus on is twitter effect on revenue. Their television contracts are huge in terms of both dollars and ratings. Given the choice of a Twitter feed for updates, television, or the in-stadium experience, even the most casual fan will pick Twitter last.
Twitter, however, is excellent for people trying to keep track of sports from colleges and universities that don't have large television or radio presence. My alma mater is a prime example. It's located in a very rural location and most graduates move far away after graduation. As an FCS/I-AA school, television appearances are rare. Only a couple of radio stations actually air the games. That leaves a streaming audio stream from the campus radio station and Twitter. Twitter has the added bonus of recreating some of community experience since many of my friends might be following along and commenting as things unfold.
Supporting my argument about the cell networks, I went to a game between my alma mater and Tennessee at Neyland Stadium last year. The game wasn't quite a sell-out, but attendance was around 99,000. Doing anything on the cell phone was an exercise in futility.