This is a tough thing to learn, and it's usually learned the hard way. Because camera makers essentially tout VR by making assertions like “allows a four-stop improvement over hand holding,” users start thinking like this: “if I can handhold my 100mm lens at 1/100, then VR would allow me to hand hold it at 1/6.” Well, maybe. But the only motion being removed is camera motion. If your subject moves during that 1/6, it's still going to produce subject blur. Looking back at my Nikon Field Guide (page 51 for those of you following along), we get 1/125 for the minimum shutter speed necessary to freeze a person walking across the frame (1/30 if they're walking towards you). This is, of course, a generalization. There's a more detailed table below the one I just referenced that shows how distance impacts the shutter speed, too. Plus the size of the subject in the overall frame makes a difference. Expecting VR to remove ALL motion is something everyone has to get over:
via Nikon VR explained.