One she is a minor. But as we know this makes no difference to the threats that are out there.
As far as training. You can’t force something on someone else. And no respectable self defence course will simulate or train for predatory street assault with weapons.
I would say the Ark is less threatening/more utilitarian, if seen or taken in evidence, but the PD is more effective. As long as she is aware that someone being hands-on, where escape is unlikely, is the "Go" trigger,
Yeah she will need to know that the only time this is to be drawn out side the house is to use it. Not threaten to use it.
Funny enough. All nonleathal protection is illegal here.

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Tbh I want her to have a folder but she has only shown interest in fixed.