Are you now a part of dumbdown.gov.uk? Flashed headlights CONFIRM what the behaviour of your vehicle indicates. In other words when you have slowed down and are leaving an obvious gap for a vehicle to pass through or enter. Even at motorway speeds it is obvious to any but a ninny that a car on the M road is leaving a gap that can be safely entered by a car coming off the sliproad. Flashes CONFIRM this. It's common sense and called indicating that I am giving way - 2 or 3 quick flashes does the trick every time. As windscreens are difficult to see through there is no other way - flashing hazards briefly can be confusing. LEAVING HEADLIGHTS ON so that you can see and be seen is, obviously, not giving way. You've guessed it. I'm one of your 'Some stupid UK drivers' (for that read the majority) who regard give way flashing as more than necessary but sensible. It also encourages calmness and courtesy.