well played...
and should be posted in every thread having a nonbeliever participating
Why? Because you think we haven't heard that opinion a million times previously? I assure you, we have.
I am an agnostic atheist precisely because I recognize the value of doubt. God might exist, how would I know?
It should be noted, informatively, that most of the people who raise this argument against atheism go far further than merely asserting God's existence, and instead seek to define God's nature. They appear quite prepared to do this without referring to their own 'advice', which is equal parts amusing and frustrating.