Personally, I don't see anything wrong with two people rolling around and trying it out by mutual consent. From the lineage on the website of the dojo in question I know for a fact that their instructor Shigeho Tanaka did just that. So did Morihei Ueshiba, Sokaku Takeda, and just about everybody from that generation. What exactly is the problem?
my point exactly...i remember reading that gozo shioda also did this...