There are lots of umpires (headed up by one referee) watching the plays. If they see anything wrong, they throw a yellow flag. Because yardage is so crucial in AF, the main penalties will be moving them back.
Quite funny sometimes when you see four or five flags flying in on a play.
EDIT: CaptJon got there before me.
Im not seeing the trophy heading towards Pittsburgh this year. Packers are all over them.