Clarification please

[SAump]

A failure to TAG UP as soon as the ball is touched on a caught fly ball. The runner may be called out for leaving a base on a caught fly ball before the ball is first touched only if an appeal is made by the defensive team.

A live-ball appeal may be made by a defensive player with the ball in his possession by tagging the runner committing the violation or by touching the base that was missed or left too early.

When a play by its very nature is imminent and is obvious to the offense, defense and umpire(s), no verbal appeal is necessary, e.g. ... a failure to TAG UP and a throw has been made to that base or plate while a play is in progress.