my New Year's resolution is to never blow my whistle unless I actually see the ball in the hands of a downed player. Many times I see a player with the ball go down but his back is to me and so the ball is hidden but I would be blowing the play dead never-the-less. I never had an IW because of this but I am going to be more careful. It will mean more delayed whistles and perhaps even more plays without a whistle but I think there would be far less whistles blown if they were only blown when the officials actually saw the ball in possession of a downed player.
You're correct Derek until you are
SURE the ball is in possession of a player who is down, you hold
YOUR whistle. However, when a crewmate sounds his whistle, the play is
OVER (even though it may subsequently be ruled an IW) and we each must
TRUST our crewmates, to help prevent any unnecessary continuing action to avoid additional problems, by repeating the crewmates signals (audible by whistle, visible by signal).
NFHS: 4-2-2-a through l advises when a ball becomes
DEAD (by rule) and the down is ended, 4-2-3 confirms, "An Inadvertent Whistle ends the down.