I'm more used to people just putting car bombs on the vehicles, though.
You should be good with the e-brakes, and should never 100% depend on your primary brakes when driving, but in practice I'm sure a lot of people get into situations where they wouldn't know to switch to e-brake if the main brakes failed, or wouldn't have time. The biggest risk to the assassin is that car accidents in modern cars just aren't that fatal -- you can hit another car head-on at 60mph and, with seatbelts, non-offset crash, airbags, etc., either walk away or at least survive at a hospital. It also leaves enough forensic evidence, especially if the driver survives and reports "my brakes just didn't work!" that it wouldn't be surreptitious.
A bomb isn't likely to be taken as an accident, either, but is at least likely to be effective.
I'm more used to people just putting car bombs on the vehicles, though.
You should be good with the e-brakes, and should never 100% depend on your primary brakes when driving, but in practice I'm sure a lot of people get into situations where they wouldn't know to switch to e-brake if the main brakes failed, or wouldn't have time. The biggest risk to the assassin is that car accidents in modern cars just aren't that fatal -- you can hit another car head-on at 60mph and, with seatbelts, non-offset crash, airbags, etc., either walk away or at least survive at a hospital. It also leaves enough forensic evidence, especially if the driver survives and reports "my brakes just didn't work!" that it wouldn't be surreptitious.
A bomb isn't likely to be taken as an accident, either, but is at least likely to be effective.