I may be in the minority here, but I really don't like the fake car sounds. People don't pay attention and saying that's because the car doesn't make any noise, isn't going to change that. I'm extra careful to watch for people when I'm driving my i3, and I do find that people are a little surprised when they realize I'm driving next to them, but don't think they would act much different in my ICE vehicle.
Case in point. Driving my 2016 Tacoma (not the loudest, but certainly not the most stealth) in the Safeway parking lot, and two people were walking right down the driving part of the parking lot in front of me. Now, I could have been rude and put it in N and reved the engine, but I just wanted to see how long they would do this before even looking. They never looked. Not once. Got to their car and didn't even register that I was there.
My point. I LOVE the fact that my car is silent. That's one of the main reasons I bought it. I don't want some artificial sound just because some people have excuses for not paying attention. I understand some will disagree, but it's just how I feel.