Two boats enter the zone in order to round the windward mark to port,
Both boats are one design keel boats travelling up wind at 5.5 knots
Boat A sailing on port and boat B on starboard.
Boat A tacks closely ahead and inline of boat B.
Boat B states that she luffed above close hauled to avoid contact with Boat A.
Boat A states that boat B was clear astern after her tack and didn't need to luff.
How should the PC apply the "burden of proof" to decide this protest?