With regards to expected value, there's a very large number of potentially very huge negative network effects from peddling a wrong theory, beyond the cost of donating for it's research.

The expected value computed by a very very well informed being may be the sum of many terms, some positive, some negative. When we didn't calculate that sum, and are thus ignorant of the sign of that sum or any other property of the result, our number for expected value, taking into account our uncertainty, is zero. Ignorance of other terms of the sum very rapidly 'kills' the expected value.

Then the thing is to note that you don't have to resort to mere passive evaluation of expected value. You can set a requirement and then people will have to pass that requirement. E.g. you can choose 'donate when X' or 'believe when X' strategy.