RE: Scary Experience
The interference issue cannot be discounted as a valid potential cause - as you say, our vehicles have become things that no mechanic (without a laptop) can ever hope to diagnose, and even then such diagnoses may be invalid or show nothing.
The MoD site I referred to did not become a problem simply by being nearby - that would be too easy. The issue depended on a number of factors coming together at the same instance to create the RF required to cause a particular effect... Like getting three bells on a one-arm bandit.
We've recently had stories of RF key blocking and cloning - not an issue for the Fluence as a physical key blade is still required before any forward motion can be engaged, but since insurers already accept this as a non-force entry to a vehicle, ignoring the effects of other external interference that can cause the effects described may well be unlikely, but certainly not impossible!