You guys must be in areas with very little ATV usage. Down here in the south every Bubba, his kids, wife and probably even his grandmother has 4wheeler and they ALL ride them. I hunt on a strictly controlled 2500 acre private parcel of land in west TN and even though there is only 5-6 of us that hunt it, we have tested time after time with ATVs and the deer just go ballistic when they hear them. More than once we have communicated by radio with one another and while one of us is in the stand with many deer around, another would crank up and ride by. Almost too the man, any bucks over 3 years old would ease into the woods as soon as they heard them, they wouldn't even wait to see the ATV. Many of the oldest does would get very panicky and may or may not run away immediately. They ALL would run as soon as they caught a glimpse of one, saw other deer running further away or saw headlights.
All that and we have NEVER shot a deer anywhere near one of our ATVs much less from one. That tells me that they equate the loud things with danger. And on two sides of our property is state land that is very limited too usage (used to be draw, now it is a very limited lease operation) and they STRICTLY enforce ATV usage too roads only. Before lastyear they couldn't even use the things at all. So I am in an area that consists of many square miles that sees little if no ATV usage yet the deer STILL hate them.
I am getting an electric cart this year. My brother has had one for a couple of years now and you can literally ride up on the deer before they even think about running. Typically if you stop they run, if you don't stop they will just watch you go by. The things are silent. I will keep my ATV for hauling deer in and out of the woods. As for hiding them, if they are dark colored and you park them in tall grass, brush or behind a tree or two the deer won't even see them unless they are within bowrange of them. As for smell, I can't help but think that they smell like anyother piece of farm equipment or truck so I doubt the deer would put 2 and 2 together on that point.
Heck I even have an uncle in MS that has poor health and he rarely hunts over 100yds away from his Big Bear. Most of the time he actually carries a dovestool, parks the 4wheeler in grass or along the field edge and uses the blasted thing for a blind to hide behind and brace for shots upon. As long as something aint moving deer very rarely are going to see it. BUT that same uncle smokes while hunting and rarely kills any mature animals. I can hear most 4 wheelers over 1/2 mile away (much further if they are going away from me or moving fast) I don't know how far a 5 year old buck can hear one. But you can rest assured that if he is within 1 mile of your ATV when you ride in, he probably knows where you are that day. So I say leave em alone, walk, drive your pickup (they are essentially silent unless than 100yds away) or look into the electric hunting buggies that are popping up everywhere now.
Check out the Bad Boy carts now THEY are the ticket for the hunter needing true offroad transportation in complete silence!
RA