Whoa! I was having fun reading this topic until I realized some are serious about a deer jumping the " whizzing" of an oncoming arrow rather than the sound of a bow. By the time the deer might hear the arrow its too late, unless perhaps its a very long shot.
Bullsi, you seriously think shooting a mechanical broadhead will make the arrow quieter? LOL. That is not a valid reason to shoot mechanicals.
cougar when you shoot a bow at a deer there is a continous sound that the deer will hear, first the bow, then the arrow through its entire flight, the quieter your arrow, the less overall noise, hence as rack attack states plastic vanes are quieter than feathers and a mechanical is far quieter in flight than a fixed head. You are right though in regards to shots 20 yards and under as far as it doesn' t matter much, but if your aiming for the lower 1/3 of the boiler room it won' t matter at all if they jump the string, if they don' t jump it you double lung them low and maybe get the heart as a bonus, if they do jump it, you still get a nice clean double lung through the middle of thier lungs.
BTW that is one of the valid reasons for shooting mechs, in addition to they do not plane and are not affected by the wind as drastically as a fixed blade.