Could be. I talked to my son and he said his cell phone didn't work at halftime when he tried to call back up to his sister about the pizza she wanted and my daughter's wouldn't work then to send out a text message with the score.
The only thing that I can be certain of, is that all call attempts to and from those cell/PCS zones were logged. It can take days to identify the specific "calls of interest", assuming that some SIM cards may have turned up....