It is, in fact, typically considered the burden of the one making the claim to prove or provide evidence for the claim and not to simply tell others to find it themselves.
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.