I skimmed the video and it seems like they never actually pick up the mouse? Would have liked to see it from various angles. Weighing 70g without holes doesn't surprise me a huge amount, with all the posts you'll see from people swiss cheesing their mice it never really reduces the weight that much. The overall/internal design seems to be the key if you're not trying for a weight record (i.e. not having excess plastic incorporated everywhere).