Not to take anything away from scent & sight "busting" many hunters, I think many hunters totally overlook the value of being "quiet" and not making unnatural sounds when going & coming from stand locations.
In particular, many hunters fail to recognize just how far sound, particularly unnatural sounds like truck doors clicking, keys jingling, the "beep" of a vehicle remote, etc. ---- typically travels in the still morning air. Not only do many hunters make too much noise, but they park too close to where they plan to take a stand.
What's more, they also greatly reduce the value of subsequent hunts at that same stand location when they make even more noise upon their exits.
In many cases, deer are able to hear much farther than they can either smell or see a hunter. And it may be that unnatural sounds "bust" more hunters than either scent or sight.