I have never heard of this road rule, but...….there are an awful lot of vehicles out there where the blinker lights just don't stand up to the question, they are in obscure places, they are barely seeable. Maybe all blinkers should be in the same places on all vehicles.
The picture just reminded me, had forgotten, the most memorable thing was how they jumped around, and spun on a sixpence for want of a better description.
How silly is this, I have seen this numerous times, seems to me it is nature. I have a lemon tree, one often finds seeds that have started growing from freshly picked fruit.