[jmkupka]

Batter's swing-momentum brings her well into fair territory, where she stays while running toward 1B.

F3 sets up well foul, on the orange bag, and yells to F2 "Foul side".

At that point, BR veers into the 3ft lane and stays there for the remainder of her run (completely inside the lane, no flailing arms or anything).

BR is hit by the thrown ball.

In this case, she may use fair territory to run, but does she also have the absolute right to the running lane? Sound like (intentional) INT to you?

My only judgement in this play is the BR came into the lane only after (and only because of) hearing F3's instruction (and seeing her position).