2. Do you really think cell phone addicted drivers will be MORE attentive when their signal starts to go in and out depending on their proximity to this driver? No, they will be more frustrated, looking at their phones more to see what is wrong, trying to redial....
I agree that this guy was an idiot, and generally speaking that's a somewhat fine argument against vigilantism, but I also have witnessed the complete inability of the justice system in the several countries I've lived in to handle even the barest minimum of enforcement of the law.
When I lived in California, I would every single day, stop cars from making illegal right turns across a bike lane when bicyclists have right of way. Me biking forward and blocking the right turn on, signaling with my strobe, could be seen as a form of vigilantism, but if I didn't do it, inevitably I would have seen a bicyclist get run over on one of my commutes.
Unless, maybe you have some clear personal definition that separates vigilantism from direct action/
If you publicly shame an alleged criminal within your free speech rights, you're not a vigilante. If you cross into harassment or stalking in your attempt to take the law into your own hands, that's a vigilante.
Deciding who can and can't use a mobile phone? That's part of the monopoly of violence that defines the government's exclusive power, just like imprisonment.
3. Just imagine being in a car accident, and some idiot in the vicinity didn't realize why traffic is slow, and takes multiple minutes to shutdown their jammer. Or is unable because they're the other party involved in the accident.