From a driver's prespective, if in doubt, wave it. We'll maybe think "yeah, I know" inside our helmets but better too much information than too little. The "trouble" is that too many drivers just watch GPs rather than read the Blue Book and think the blue flag means you have to let the car past - but if they back off unnecessarily, I'm happy to take the place off them
Ha, ha - crossing posting with conflicting advise!