All of the elements for a really good conflict are in place with this set-up: Symkyn's more blatant than usual cheating of the university prompts John and Aleyn to boast that they'll prevent him from doing it again; having publicly announced their intention, they can't back out now. But we know Symkyn's a proud guy, not to mention supremely unethical. Will he figure out a way to cheat the students despite their stratagems?
Symkyn makes the conflict between himself and the clerks totally clear. He also clarifies that he sees the conflict as one between the learning of clerks and the common sense street-smarts of peasants like him.
Just when we thought the conflict was over and Symkyn the clear winner, John and Aleyn decide it's too late to go home tonight. The fact that they bed down in the family's shared quarters, in close proximity to Symkyn's wife and daughter, and that they've got a bone to pick with Symkyn, leads us to suspect that something naughty will soon be afoot.
Aleyn and John get "payback" for their stolen corn. Everything in the story has been leading up to this, from numerous double-entendres in the tale's scenes and language to the opportunity presented by those shared sleeping quarters. When Aleyn calls sex with Malyne "esement," meaning both payback and physical release, we know that the sex is pretty much a done deal.
The minute John moves that cradle, we know disaster's about to strike. Sure, it causes Symkyn's wife to hop into bed with John, but since Aleyn doesn't know a thing about it, he's sure to hop into the wrong bed, too! Sure enough, he does, and to make matters even worse, he brags about sleeping with Malyne to the last person he should. Now the reader is left wondering how Symkyn will react to this slight to his daughter's honor.
The tensions that have been brewing between the characters, and the suspense that has been slowly building, get released here in physical violence. Finally, the rivalry between the clerks and the miller, which was never stated outright but always implicit, is out in the open.
John and Aleyn are the clear winners in this conflict, getting not only their full amount of corn, but also something "extra" in the sex they have with the miller's wife and daughter and the beating they give Symkyn. The narrator draws a moral from the story, saying that this punishment served Symkyn right for cheating his customers.