An NFL penalty flag weighs 1.9 ounces. A football weighs about 14 ounces. To throw a penalty flag 31 yards is like throwing an ornately wrapped golf ball from home to second. Talk about throwing the flag at the spot of the foul — the back judge clearly thought he saw some holding back at the line of scrimmage and wasted no time asserting himself, even though those calls are typically made by someone less than 100 feet away from the play.
[H/T Extra Mustard]