The only issue I’d see with that convention is that in many scenarios in which you’d use it — other driver makes room for you to merge, brakes early to let you turn left, and so forth — you (should) already have half of the hazard lights actively repeating, which could muddle the message. But otherwise I like it.
Another random convention I learned early on was rapid triple-tap beams (i.e., like a strobe) = “speed trap ahead”
I remember reading a while back that the hazards twice = thank you.
I’d certainly interpret it that way if it fit.
The only issue I’d see with that convention is that in many scenarios in which you’d use it — other driver makes room for you to merge, brakes early to let you turn left, and so forth — you (should) already have half of the hazard lights actively repeating, which could muddle the message. But otherwise I like it.
Another random convention I learned early on was rapid triple-tap beams (i.e., like a strobe) = “speed trap ahead”