Arguments drawn from intuitive ideas about what Earhart, Noonan, or other characters in this research could have done, would have done, or should have done are moot: "In American law, a matter is moot if further legal proceedings with regard to it can have no effect, or events have placed it beyond the reach of the law. Thereby the matter has been deprived of practical significance or rendered purely academic.".
Guesses about what people "coulda, woulda, shoulda" done are indefinitely arguable, but undecidable (unless, of course, one has the power of reading the minds of the dead). In calling an argument "moot", one is not saying that it is known to be false but that the truth or falsity of the proposition is irrelevant to determining what, in fact, the character in question did think and do.
"They could have ..."
Strange things do happen. People make choices from a wide variety of possible courses of action.
From the fact that some things could have been done, it does not follow that they were done. One may concede the possibility of an action and deny that the action took place. Evidence is required to decide the question of whether a historical agent did or did not do what could have been done.
"They would have ..."
"In writing about historical events never, ever say 'would have.' If you can't say 'did,' say 'might have.' 'Would have' masquerades a guess as a fact" (Gillespie, private correspondence, 21 December 2010).
"They should have ..."
Although we should obey the civil and moral law, humans often do not do what they should do. No historical fact can be deduced from a consideration of what is logically, rationally, socially, or legally required; an estimate of probability may derive, in part, from such considerations. From the fact that a speed limit exists along a stretch of highway, it might be legitimate to suppose, as a general rule, that most people drive at or near the speed limit on that highway. The actual speed of a car involved in an accident on that highway may deviate significantly from the norm (far slower or far faster than the speed limit), even though drivers should drive at or near the speed limit under most circumstances.