NCAA - Need it for all changes of TEAM possession where possession is gained by a team inside its own 5 and the momentum exception might be applied. Also need it for all 4th down fumbles by Team A beyond or behind NZ, close or not to the sideline) as well as on all trys. When a hand-off or backward pass occurs beyond the neutral zone or when there is no neutral zone. When a scrimmage kick ends inbounds. When a Team A player illegally touches a free or scrimmage kick. When necessary to mark forward progress when the runner/passer is driven back.

It is NOT needed when the snapper/QB exchange is not successfully completed and the ball comes loose