Interesting thoughts. So I dug a bit deeper. The main difference between the 2 is fake means with the intent to deceive. So if your car has no engine, but you want people to believe it does, you would employ fake exhaust sound. Which was made artificially.Considering the fact that ev's don't emit an exhaust tone, it should be noted that they are embossed with one; therefore, it's technically not fake, just artificial.
An example of a "fake" exhaust noise would be like a Toyota Camry playing a Top Fuel dragster soundtrack at every stop sign or light.