I don't really remember the ep that well, but off the top of my head, I think a more revealing and simple thing would have been a reflex action. Catching or swatting at something thrown her way, for example. No matter how hard you train yourself, I really doubt that you could get yourself to catch an unexpected ball (or other object) with your off hand.
As for myself... I'm a strong righty in the sense that I will, by instinct or preference, do most things with my right hand. OTOH, when I broke my right arm as a kid, I found myself running into a lot of difficulties. Since then, I've made sure to practice doing most common tasks with my left hand, to make myself as ambidexterous as possible. My dad has helped with that, actually. He needs a lot of elbow room at the table (a fact which he refuses to understand or aknowledge, whether it's pointed out subtly or point-blank), so I've quietly taught myself to eat lefty. Whenever he sits on my right, I simply tuck my right hand in and use my left as my primary. I'm still a little shaky with a spoon, but I can use fork, knife, or chopsticks with either hand.
On the test, I come out 50/50. I never learned to draw a profile, for some reason. I draw circles and clap hands righty, but I clasp and fold arms lefty.
As for writing, I have this talent. I can write illegibly with either hand.
Thank goodness for keyboards.
I do prefer to use my right hand, though, and my writing is slightly more legible when I do so.
I'm not sure about this hooked vs straight thing. I hold my pencil with three fingers. It's braced against my middle finger, but controlled by my thumb and first finger. My hand ends up basically on the line, and the pencil isn't really pointed towards or away from me. I tend to have it straight up and down, although as I move across the page, I sometimes shift my hand so it points slightly towards or away from me.
Of course, I have some personality traits which, I'm told, are associated with a strong left-right connection. So... <shrug>
Anyway, interesting discussion.
Paul
