I got to thinkin', if all those batteries were in series, that'd be over 40V. But having 4 series sets of 4 batteries in parallel would be around 6V, right?
The video is a hoax, according to some. I'm not sure. I imagine it could vary from brand to brand. I imagine the bigger battery companies would be especially worried about people following the trick, and so would be less likely to load up 32 AAs like that.