Obviously it is telling you "DON'T DO THAT"!
How would you feel? Your sitting peacefully at a stop light, probably eyeing that catchy looking Miata next to you, and all of a sudden somebody kicks you in the ass as hard as they can?
I mean, come on,, you'ld give quick look, then a heck of a jump, then maybe a few steps and look back to see what that was all about. Then run like hell to get away before it happens again.
Obviously I don't have anything of substance to offer. In the "day" (carb) that would have been the accelerator pump. Fuel Injection, don't have a clue.