ABS is VERY proficient in handling different surfaces. In fact, THAT's where it shines most, compared to human control.
As I said, what could have been a problem was her having a more pavement oriented tire, so having lesser grip on the gravel road, and what could have been another problem is, she might not have braked as hard before turning, though ABS could have helped with that as well.
The lower grip level maybe was too low for her turning speed (and skill) at all, but the change of surface would NOT have been a problem for a modern ABS.
"Why not stay in disguise all the time? You know, look like everyone else."
"Because we shouldn't have to."