LOL, probably they can call their stupid god like casting bad words when gets loss or it could be also calling the real god when things gets good or bad. It will just depend on the scenario.
But, I do not really believe atheist has no God at all. They just deny the religion but no one could not feel a high beings with super powers that created the world and the human beings on this earth.
Its quite natural for humans to believe in their god either they are happy or sad. But yes you are right, when we have bad times, we return ourselves to God because we know we are helpless and their materialistic world isnt working for me. But if someone thinks gambling can turn him to God, well that is good, but unluckily it doesnt happen mostly. Exceptional cases exists but this isnt normal practice.