Well, presumably if working harder on their submission was their utility-maximizing choice, they would have done so already sans experimental manipulation; if any more quality time was used up, it probably came at the expense of some other activity...
It looks like I badly misunderstood your comment. When you wrote "the researchers," I thought that was a coy way of referring to yourself in reference to the two experimental results of which I questioned the ethics.
I'm not arguing for the optimality of compliance with an IRB or other "ethical" guidelines - I'm doubtful they do a reasonable job of creating morally optimal research protocols, and they clearly prevent the discovery of certain interesting or useful results - like your results from these posts that relied on deception. An...
Master copy lives on gwern.net