[A]s Pascal said, if you are mistaken (you have faith, and "God" does not exist---a definite possibility), you have not really lost anything.Game theory does not apply to beliefs, it applies to decisions. A decision with no cost is no decision at all; to decide to believe sans evidence in God if that decision entails nothing about one's life is no belief at all: Such a "believer" is just as much an atheist as I am.
In practice, I think tell the thousands (tens of thousands?) of children molested by pedophile priests and tell them that their decision and their parents' decision to believe in God was without cost. Tell the people, many of them desperately poor, who have contributed their hard-earned money to televangelists that their decision to believe in God was without cost. Tell the millions of gay people, wracked with guilt, shame and neurosis because they've been indoctrinated by almost every Christian and Muslim sect that their ordinary desire to love one another without harming anyone is horribly sinful that their belief in God was without cost. It's too late to tell my late grandmother—but there are millions of others in the same situation—that her belief that God wanted her to stay married to an abusive man for forty years was without cost.
Without cost my ass.