Pascal's mugging applies when the sheer magnitude of the benefit is a substitute for any argument that the benefit is actually likely. X-risk charities typically are of the form, "This probability is small but nonvanishing because Y, and Z. When you multiply it out, the big benefit makes the expected gain large despite the attenuating factor". Some go further and argue that the probability is not small. None simply rely on the magnitude of the benefit without also arguing for plausibility.