I could adopt the attitude some in this thread have espoused, namely, let her do poor technique on me without comment or avoid her altogether. Neither is a tenable solution in my mind.
Why? You seem to feel responsible for teaching her.
....I did speak with my sensei about it after practice. ... Perhaps ... if her attitude continues, he will do something about it
Okay, that sounds like a good solution. In the meanwhile, what will you do? Correct her?
Even if she is violating some expectations about how she should behave, in our dojo at least it really would not
be your job to fix it. From that perspective, even if she was wrong, she was also right.
You talk about her "poor technique;" is it clear to you
how much of the deviation between her technique and your expectations reflects poor execution and how much reflects a difference in style from her old school? If you allow her to do the technique, just take ukemi, and let your sensei be responsible for teaching, you may learn something no one else at your dojo can teach you.