Of course they could. And they should! Statistically, if every single sentient being makes this argument, more sentient beings will be right than wrong.

To quote:

> Given the prevalence of the four different blood groups in the cartoon above, the most profitable strategy here would be to bet on "A", as that gives you the greatest chance of winning. Another way of looking at it, is that if everyone adopted that strategy, the bookmaker would lose the most money.