find out who threw it. But it is a prime example of why stadiums and law enforcement around the country need to start taking a much tougher stance against any fan throwing stuff onto the field. Start charging people with attempted assault and this crap will stop.
And yes, I realize even BYU fans have been guilty in the past. The behavior needs to stop. It needs to be shown that it is unacceptable to do this as yes, the people on the field can get hurt.