Bottom line, if you're stupid enough to leave an electronic device in the rain then you deserve to have it break on you.
There's no if's or but's, no other argument, nothing else to discuss.
You simply do not leave any electronic item, whether it's an iPhone, a Blackberry, a Xbox 360, or a 42" Samsung LCD television, outside in the rain ... they will all break, and there is no guarantee of durability.
I mean, if you believe there is some kind of durability expected from electronics devices being left in the rain, try this for an experiment.
Dip your hands in water, then turn on a mains socket.
Same result ... BOOM.