I used to be very anti-ATV/UTV for hunting, because of what I've seen on big clubs that allow hunters to ride ATV right to their stands. Some even build tower stands with covered ATV "garages" underneath the stand. In those instances, I've watched as deer quickly cleared food plots as soon as they heard an ATV being fired up, often a LONG distance away. However, I also have the experiences generated from 30+ years of running trail-cameras and 21 years of running trail-camera censuses. It didn't take long to learn that the fastest way to kill a camera site was to walk to it frequently. All that human scent going to and from the spot, and concentrated around the camera itself, really shuts down older deer activity in the area.
So you have deer that become highly sensitive to ATV traffic when that traffic is associated with hunting, and yet constantly walking to a stand can shut down deer activity in the area as well. What's the answer, walk or ride? I really don't know. Once I began using video mode on trail cameras I learned some really valuable information. Over and over I got video clips of deer suddenly snapping their heads up and looking off in a particular direction, then rapidly leaving the area. The next video is me pulling up on my ATV to check the camera (I only place cameras where I can drive an ATV right to the camera. This reduces scent left on the ground). Checking the time stamps, the videos invariably will be less than a minute apart. The video of the deer reacting is proof the deer are hearing me coming on my ATV and getting out of the area. So even though I ride an ATV around the property regularly, all year, deer are still reacting negatively to an approaching ATV. However, what is most interesting is that the same deer that ran away from the approaching ATV are often right back in front of the camera 5 minutes after I leave.
So which is the best practice? Walk long distances to your stand and lay down scent that reduces deer traffic in the area, or ride closer on an ATV that certainly spooks deer, at least temporarily? Now I would never practice nor recommend driving an ATV right to the stand. On the other hand, walking long distances to stands is probably not the best practice either. I really don't know where the "inflection point" is between the two practices.