I read (on a blog) that people at the game were unable to use their cell phones for a period of time during the game.
I can vouch for this. My sister in law was at the game and called me to wave hello. I tried back moments later and could not get a signal. Quite honestly, I don't know if this is unusual.
Yes, someone reported that as the event unfolded. Some freepers were trying to get their family members who attended the game on the phone, and vice-versa.