While I agree that I'm hesitant to invoke the 30-yard nuclear bomb, I think it's more likely to see... shall we say, "obvious"... PI than just goal line. 3rd & 20, and Bubba gets beat at the line of scrimmage by Skippy. Last year, at the very least, A gets a first down in that situation. 15 yards and a replay of 3rd down is a lot more attractive to a defensive coach than the kid getting burned for a long first down or a TD.