Providing a natural explanation for lightning which in turn rules out an angry God is one thing, but consider this; I could state that I don't have a stash of cash (one million dollars) hidden somewhere, but how could I possibly prove that I don't? What would the evidence for this nonexistent cash look like? The evidence doesn't exist. To simply believe that I do have a hidden stash without a shred of evidence to support that belief, and to consider that it's just as valid a belief because there is no evidence for disbelief is just plain ignorant. In real life ignorant people fell for Bush's notion that Saddam Hussein had to prove that he did not have WMDs. It was impossible for Hussein to prove that he did not have them. However, there's no shortage of ignorant people, the Bush supporters proved that on a regular basis.
Remember, the goal is to provide evidence, not prove. But again, this relies on the person defining their God. I'll refer to your particular example:
You've set parameters. One million dollars.
Could you even acquire this large sum? What kind of job do you have? Do you work at McDonalds? As a fry cook or are you the CEO? If you are a mere fry cook (or other low-paying job) do you know anyone with possession of one million dollars? If so, what would their motives be for giving it to you?
Realistically, the stash is hidden somewhere on Earth. This very much reduces the search area from "somewhere". What would your motive be for stashing it somewhere? To hide it from someone else? Because you're a loon?
We can create a probability density distribution map of where the money could be based on your geographic location (i.e. Say you live in Spain, it is unlikely the money would be found in the middle of the Pacific Ocean, but very likely to be found in Spain which could aid in searching for it).
These are all questions with definitive answers. Answers that will eliminate possibilities that will determine whether or not you actually have a stash of money hidden somewhere. It's an a** backwards way of going about proving it true or false, but assuming you know "ALL" possibilities you can "prove" the negative, provided they are testable and falsifiable.
It's certainly possible for someone's God to be testable and falsifiable. But that depends on how they define it, which is central to the issue. Not all definitions of God can have the proven negative. And even more cannot even have evidence for the negative. But some probably can because the definition is so variable.
And I agree with you that anyone who takes the positive claim on the grounds that the negative is yet unproven is damn irrational. The tooth fairy is still yet unproven. Equal evidence for and against. Shall I knock out DarkSun's teeth so he can put it under his pillow and make a few bucks
? After all, his belief in the tooth fairy is just as justified as my non-belief in the tooth fairy.
And if he claims to have non-belief in the tooth-fairy, he'll have to explain the variation on his stances. Why the special spot for "God" (that he is reluctant to define)?