http://blog.ericelias.org/blog/2012/02/17/why-the-nfl-bans-ipads-and-oth...
The NFL banned the use of certain technologies prior to the use of a game because someone one can create an application that would use the plays and statistics to calculate the next play for a team... so basically technology can help a team win a game. For instance iPads are banned... what about iPhones? Can't they also have apps?