Is it a limitation of the GPU quality or the VRM?
If it's just a bad core, then I see at least two alternative (more sensible?) ways of handling the video validation question:
a) Find the highest frequency done on stock VRM that was posted before competition kicked off and use that as a video validation threshold.
b) In addition to a), if someone posts a video of stock VRM running higher, move the threshold frequency upwards.
In both these cases, everyone "knows" that the stock VRM can handle frequency X allowing people with ePower also bench at frequency X (or X minus 50/100MHz, to give guys pushing stock VRM and making videos a frequency advantage) and be less worried about killing their cards.