Unless you're blind, or happen to be looking the other way when the drunk in a prius bears down on you. Which is why some sort of fake engine noise will eventually be mandated (if it hasn't been already).
When you're in front of a car, you don't hear much engine noise. Especially since there is very little load on the engine at speeds fast enough to hurt people (unless they're testing their 0-60 time). What you DO hear is road noise from the tires, which is not any different between electric and ICE vehicles.
The Nissan Leaf, for instance, makes an artificial electric vehicle noise until about 20 mph... after that you wouldn't be able to hear the fake engine noise over the wind and tires. Go listen to one drive around a parking lot though, and you'll mostly hear it leaving.
I'm kind of against the noise in general, as I don't think many blind people are being saved by the artificial noise (but rather from aids, the real sounds, etc), and short of the driving honking, some fake engine noise isn't going to save you from a drunk prius bearing down on you.