I honestly don't understand the thigh grab wiki. I can sort of get the clarification on ass grab, but who's mistagging post #5120312 as thigh grab? The leg grab bit also feels rather presumptuous, as leg grab didn't get its wiki until after thigh grab did, and there's no forum evidence to suggest that leg grab was intended to be mutually exclusive with individual leg sections.
Leg grab should be used for exactly what its name suggests, and thigh grab should imply it, as well as extending down to above the knee because really who actually cares about that level granularity. Nothing I could find treats the lower thigh as separate from the upper thigh, either, it's all just thigh.