The 2CV had this setup from 1948 to (I think) 1970, though I don’t think the major motive for this indicator arrangement was safety; I think Citroën was trying to make indicators that could be seen from all corners of the car with just two lamps, to keep things cheap. Eventually, they gave in and put indicators on the front fenders and in the taillights, but they rode this method for a good long while.
Now, Fisker isn’t even the first to put indicators on the actual D-pillar, as we’ve had Volvos (and other cars and vans and SUVs) that have been doing this for a while.