[glenstein]

I think that in addition to the problem of boosting interest by concealing probabilities, you have the added problem that probabilities are difficult to intuitively grasp, even if they're straight up given to you.

The same way that a person can have a correct (at least within a few orders of magnitude) understanding of their numerical odds of winning the lottery, yet still go on purchasing tickets. Our intuitive grasp of the idea of one in a million, billion, trillion, etc is such that those odds all "feel" the same. But those differences might make all the difference in whether purchasing a lottery ticket is rational.