wonder if it has something to do with law enforcement restraint approach, i.e. two LEOs restraint an unruly samurai or some such. if it is, the wouldn't that make the practice to counter LEO?
Phi and others,
For what it's worth, my understanding of the reasoning behind Hakkoryu's teaching of defense against morote (two hands on one) is precisely the above, though not specifically against law enforcement folks. Morote may have been an immediate attempt by one person to prevent one from reaching for a tanto or wakizashi, or may be an arresting technique used by two people. Hand-me-down techniques from pre-Meiji times?
Another reason I feel the morote attack would only happen in last-ditch scenarios such as these is because we're taught to strike whenever a hand is free; meaning it would generally be unwise to seize a person's arm with both hands unless they had already (or were about to) draw a weapon.
P.S. Phi, you may be more correct than you know...in Hakkoryu's Shihan-gi we're taught to prevent efficient tying of our hands so as to make easier an escape later on.