This is satirizing the view of people who feel observational studies - studies in which everyone is treated with the experimental medicine and the response of the entire group is evaluated - aren’t clear enough or rigorous enough to prove that a drug works. True, these studies sometimes lack the clarity of a perfect randomized double-blind study, but as we see with the parachute, sometimes the results are pretty clear anyway. And in a life-or-death situation, no one wants to take the chance on a placebo. In other words, the “advocates of evidence based medicine” are being “challenged” with a little sarcasm. Inglis-Arkell 2014