“making assasinations easy, such as jamming the accelerator on Hastings Mercedes to full speed”
Impossible unless they had physical access to the automobile in order to install something they could connect to remotely. That simply cannot be done without some type of physical modification to the vehicle. The onboard computers installed in vehicles which could control such things have no native wireless capabilities, and are completely separate from any cellular service in the vehicle, like OnStar.
I understand what you are saying, but if I’m not mistaken, there are some vehicles that do use some sort of remote connecting for starting the engine. I really don’t know enough about the systems Mercedes uses to say one way or another if it could’ve been done. It would be likely that the computer systems being used on higher end vehicles would have some sort of wifi connection for use with diagnostic machines, but perhaps it’s still a hard wired process.