The antecedents of aikido and their relationship to weapons styles is an interesting subject, but I think it's a bit of a digression from this discussion of the wrist grab. If the purpose of the wrist grab, as stated above, is to control the "weapon hand"...well, then it kind of matters if there's an actual weapon in it, doesn't it? Nowadays that's much less likely to be the case. So, we're back to the question of what "with intent" means. What's your intention? To stab me with an imaginary knife? Those knives, I'm not so worried about.
OP here. The purpose of the grabs that I was talking about was to stop someone from punching me. Was I sure if they didn't have a knife, no. After getting the arm the serious intent was to stop them from doing anything further by using them as a weapon and hurling them into objects.
Most muggers I've entertained can't punch worth a damn. Grabbing their arm and throwing them was an untrained, but effective response.
I was interested in that the usual roles of nage and uke are pretty well jumbled. The attacker really looks like they have the nage role here as far as using aikido goes.