Fact is you SHOULD be able to leave your keys in a car without someone assuming the right to steal it because the owner was being careless. The owner left the keys, that is all. No-one has a right to them help themselves.

I absolutely agree. But you'd be bloody stupid to do it. And I am sure that your family would blame you for that stupidity when the family car went missing.

I specifically said that I did not accept the idea of "shared responsibility", with its implication that the guilt of the perpretrator is someehow less if the victim is seen as at fault as well. In fact I think it is nonsensical to think that way.