"Obviously, the existence of a god is a complex notion and hence cannot be the the default, but is something that must be demonstrated, i.e. must have supporting proof to be accepted."
Like water turning to blood, raising people from the dead, turning water to wine, etc, or like God speaking from a mountain, food falling from heaven, a fire in the sky at night and a cloud during the day?
The problem with continually asking for proof is that 2000 yrs down the line another guy is sitting there demanding proof from a god that has given more than enough already.
god then has two choices.. sit there at your side for constant proof which no one would choose sin, or well i guess one choice since atheists won't be happy otherwise.
If you want proof, there is a book that god wrote that gives many many examples as well as ways to test his promises and existence.. but you have to be willing to try......don't listen to any other man's interpretation of this book go read it yourself.. find the promises and examples yourself and test them for your own knowledge.. if you don't but yet still spout this self serving tripe.. well then i assume you're like every other atheist i've ever met or heard talk about god.