OK, first of all, yes the design would work, but legally it would not work. It would be nice as a neat decoration on the wall or shelf but not to carry around. You could go to an online store and buy her a really nice sword or other weapone of choice. It could even be a nice gi or design to add to her gi. If you want her to feel confident buy her some pepper spray. If you want her to feel more than confident for her sake keep her in MA. For your sake if you were a blackbelt and have gone through the training you would not have even thought about cruching the guys phone. This is a careless act of anger and if you were a blackbelt you would have gone through the discipline if taught to not do that. I would have simply asked him to walk out of the theatre to talk if he needed, but not while the movie was going. if he had a problem with that, as most would, then he might confront you, this is where your MA traing comes in handy. you mentioned that you want the element of suprise but you would suprise him enough when you kiss his ass all over the theatre. He would then be the attacker if he came at you, not you acting like a jerk and crushing the phone.
I think that sums up everything.

OK, first of all, yes the design would work, but legally it would not work. It would be nice as a neat decoration on the wall or shelf but not to carry around. You could go to an online store and buy her a really nice sword or other weapone of choice. It could even be a nice gi or design to add to her gi. If you want her to feel confident buy her some pepper spray. If you want her to feel more than confident for her sake keep her in MA. For your sake if you were a blackbelt and have gone through the training you would not have even thought about cruching the guys phone. This is a careless act of anger and if you were a blackbelt you would have gone through the discipline if taught to not do that. I would have simply asked him to walk out of the theatre to talk if he needed, but not while the movie was going. if he had a problem with that, as most would, then he might confront you, this is where your MA traing comes in handy. you mentioned that you want the element of suprise but you would suprise him enough when you kiss his ass all over the theatre. He would then be the attacker if he came at you, not you acting like a jerk and crushing the phone.
I think that sums up everything.

If you have a concealed weapons permit, does that also constitute nunchucks or just for firearms?

Yes, you will run into leagal problems carrying these. It is after all a "weapon". It's not like a cane or using your keys or some other "legal to carry".

I'd also be concerned about "over confidence" in being a 10 year old black belt and her trying to use a weapon that will only get taken away from her. I can't imagine that a 10 year old can be a "black belt" in anything, let alone use such a weapon effectively. If anything, this may end up encouraging her to stay in a situation that she should have run away from.

Awareness training and other self defense to help kids escape from a dangerous situation is good. But giving them black belts and weapons training just seems detrimental.

If she already carries a house key, teacher her to use it to poke eyes, etc. but also reinforce the sitauations where she should try that. Always try to run away first and never try to fight unless actually abducted. You can also teach her to use a pen, jewelry and other such things.

"as I want to make a nunchuk that is designed to hit pressure points, without coming into very close contact with the opponent, who may be armed. "

It would have to be very long. As it is now, using a standard nunchaku has you just about a foot away.

The idea of incorporating the weapon into clothing also comes with a flaw. How do you get it out and snap it together in an instant. If it's a belt, it will take at least a few seconds to recognize the situation, get the belt off and "activate" the weapon.