The only difference between this and https://xkcd.com/1958/ is that this attack confuses cars from certain manufacturers but not human drivers, and I'm not sure that that distinction is important.
Is this attack actually in anybody's threat model?
Is this attack actually in anybody's threat model?
There are people out there who don't want autonomous vehicles on the streets. Whatever their reasoning is isn't particularly relevant, because if someone wants to accomplish a given end, this has potential as an attack vector.
A cone is not an example of a dangerous attack.
It's not like cones cause the cars to jam the accelerator.