I disagree. The burden of proof is always on those who say there "is" something that others don't see. Just like the burden of proof is always on the accusers in a criminal case -- they are the ones who said you did something, and you say you didn't. They are the ones who have to come up with the evidence.
If I say "math does not exist," all you would have to do is scribble an equation on a piece of paper, and I would be proved wrong. So, until I see some compelling evidence, I can't accept that believing in a god is a reasonable thing. And that's the point -- it's not reasonable, and it can't be argued. And no one should be expected to prove the non-existence of something. If it in fact exists, it should be a relatively straight-forward task to demonstrate it.