Spurred on by the accident claims vultures who call you within 24 hours of any notifiable traffic accident, it would appear that there is an increasing number of deliberate accidents involving flashing headlights to tell you to pull out, then having someone drive into you.
Flashing headlights is only supposed to be used as a warning, but as everyone knows it is used well outside of that remit. The Highway Code says:
110
Flashing headlights. Only flash your headlights to let other road users know that you are there. Do not flash your headlights to convey any other message or intimidate other road users.
111
Never assume that flashing headlights is a signal inviting you to proceed. Use your own judgement and proceed carefully.
The problem is that if someone flashes you to emerge in busy traffic, and if you can see that they’ve stopped, and if you can see that it is otherwise safe to emerge, then there is every reason for you to do so. If they are scammers and decide to drive into you, they could just as easily have done it if they hadn’t have flashed and had just sat there obviously inviting you to pull out. The flashing headlights thing is a red herring.
I make it clear to my pupils how they should both use and interpret flashing headlights. There’s no point saying “don’t do it. EVER”, because they will once they’ve passed, so it is important they understand how to do it properly.