Just for information here is the NCAA rule on this.
RULE 8, SECTION 5, ARTICLE 1. It is a safety when:
a. The ball becomes dead out of bounds behind a goal line, except from an
incomplete forward pass, or becomes dead in the possession of a player on,
above or behind his own goal line, or becomes dead by rule, and the defending
team is responsible for the ball being there (A.R. 6-3-1-IV; A.R. 7-2-4-I; A.R.
8-5-1-I-II, IV and VI-VIII; A.R. 8-7-2-II; and A.R. 9-4-1-VIII).
The provision that applies is that the defending team was responsible for the ball being downed in the end zone.