D-U-S and Rod E I see exactly what your saying, and agree with you 99%, I'm just purely ensuring that both the for and against argument are put forward on this topic.
Consider the scenario again of all signals over London being jammed. All the aircraft in the sky at that point would struggle like hell to get their planes down and I doubt it would happen without a serious accident.
A passenger carrying UAV would certainly crash, no doubt. That is why we'll never see a PAX UAV in our lifetimes.
Now imagine a CARGO carrying UAV in the same situation over London. It's loss-of-comms software would turn the aircraft towards the sea, fly as far away from land as possible and ditch. Loss of life zero (unless there was a ship in the way!). Loss of cargo and hull - insured.
I'm going to maintain there's a real market for cargo carrying UAV's - I don't mean 747 sized but one's capable of carrying 100kg 1,000 miles across the UK, Europe or the States.