Flash hazard lights to say "thank you"

[jack]

For a while, I've noticed cars flashing both indicators simultaneously (presumably by turning hazard lights on then off again) to say "thank you" for letting them in.

I think I first noticed it by lorries -- google suggests it may have been a lorry driver custom first.

I really like the idea of being able to say "thank you" or "sorry" as well as "please" or "get out of my way" when driving.

Am I right that it's new, or did I just not notice when I started driving?

Presumably it's not allowed (just like flashing headlights to say "excuse me" or "after you" or "do you know your lights are on/there's something wrong with your car/etc" was never an authorised use according to the highway code). Is it a bad idea, or not?

Comments

[syderia]

While I do appreciate having a way to thank people on the road, which where I live happens by raising one's hand in front of the rear-view mirror, I don't think that using the hazard lights to do so is a good idea.
For me, the reflex when seeing someone's hazard light on should be "slow down - pay attention - figure out what the danger is". Using them to thank people, a gesture that might happen more often than danger on a road, would dilute that reflex and possibly make driving more dangerous.

[damerell]

Hazard lights are largely diluted anyway by their use to mean "I am parked somewhere stupid." Particularly vexing when one is obscured - are you pulling out, or just an idiot?