Originally Posted by the Pheasant
In general riding, the harder I brake, the less rear brake I use. Sometimes I use no rear brake at all. If the road is wet, I use more rear. Only when filtering through traffic at low speed or if I suspect the road is slippery from ice or diesel do I use rear only. That said, I occasionally drag the back brake when accelerating on a greasy surface. FWIW I haven't locked the back brake unintentionally since as long as I can remember. Nor the front.
Seems to me it is important to teach learners to learn to use the rear brake in regular riding since it can be very useful. Without practice at using it, the rider is denied the ability to use it correctly when needed. Learn to use it and then use it or not as you see fit.
And while you're at it, teach her how to downshift while braking. It could save her life.