Despite being right-handed, I learned to write watching left-handed people, so I know the feeling
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In any case, if the pen tip makes contact *before* her pinky finger does, this *should* kick in a global "palm rejection" and ignore everything except the pen (unless somebody at lab126 screwed the pooch). Lifting the pen without lifting the hand should keep behaving after that (again, assuming someone actually thought this through).
Even if it works, that's... not very practical, bit it might be worth a try
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