In review, the video states that "belayer positioning is very important in ice climbing due to falling ice.
They have three guidelines that should be remembered:
1) During ice leads, consider down-anchoring the belayer so that they don't get pulled into falling ice.
2) When toproping, it's important to consider anchoring the belayer away from the base of the climb to avoid falling ice.
3) If you elect to use a down-anchor (ground anchor), the belay loop should be used, and not the back of the harness.
--Jason D. Martin