The human eye is attracted to movement rather than static images. In forests, even lightly wooded ones, you will never see the animals unless they are moving or you have extra keen eyesight. Often times when they are moving, they are mostly obscured by trees or brush, making target identification difficult. Therefore, any movement seen in the forest could very well be the target animal.
In the old days, there was a low density of hunters. The NRA safety rules had yet to be established. People weren't too smart about hunting. They would often hose down the area where movement was spotted and then go check it out. The problem is, if that movement was caused by people, you likely just killed someone. Hunting was rather dangerous in these days.
Because of the movement vs. image thing, many hunters will still prematurely get an adrenaline dump and get trigger happy. A number of precautions can be taken to insure you don't get shot during deer/elk season.
1) If going hiking, jogging, etc during hunting season, NEVER WEAR BROWN. Movement combined with brown color will make dumb asses moresure of their target.
2) Wear orange, even if not hunting during hunting season. With the exception of poisonous frogs in the jungle, there is absolutely nothing in nature that looks neon orange. It is bright. Moving orange attracts attention like crazy, and since it is immediately recognized as a non-natural it may diffuse the situation.
3) Avoid riding through the woods on horse back. Brown horses in particular with people up top look an awful lot like bull elk with huge racks. Horses and elk in general look a whole lot alike. If hunting on horseback, decorate your horse like a Christmas tree of neon orange. And hope bubba's great grandpa who is still drunk from drinking too much wild turkey 101 from the night before realized elk are not orange.
4) Avoid being in the forests during deer season. There are a lot of really stupid hunters. Plus, in rifle hunt areas, bullets go a long way, and not everyone is smart about their back stops.
While hunting is no where near as dangerous as it was 60 years ago, it isn't exactly safe either. Take precautions, whether you are a hunter or otherwise, to avoid getting offed by some idiot fudd with grand pappy's modified mauser 98 bubba fucked after WWI.