Alison is the only female figure in "The Miller's Tale" by Geoffrey Chaucer, and she is surrounded by three male characters.  

John is Alison's husband. He is a carpenter and a rather naive, gullible man, which he demonstrates in nearly every encounter he has with anyone in this story. His worst transgression, at least as far as his eighteen-year-old wife is concerned, is that he is an old man. 

...he had fears
Of being a cuckold, so advanced in years.

He is jealous of his wife, and for good reason. She is an earthy, sexual creature who always seems to be looking for her next conquest.

Nicholas the Handy is a match for Alison, a sexual being who goes after whatever he wants; in fact, he crudely grabs Alison when he sees her for the first time. He wants her, and he contrives to have her.

Poor Absalon is just a foolish, rather prissy young man who claims to be in love with Alison. All he hopes for is a chance to get near Alison, even serenading her under the very window where she and her husband are sleeping. He wants nothing but one kiss--and he gets it.

Alison is part of an elaborate (but effective) plan to dupe her husband so she can spend the night with Nicholas. It is an awful act of cuckoldry, but it is one which John practically anticipates from the beginning of their marriage. Alison is also the instigator of a crude and cruel act against the lovesick Absalon. When he asks her for just one kiss one dark night, she presents her uncovered rear end to receive his kiss. It is a humiliating moment for Absalon, but to Alison it is the height of high mirth and merriment.

Judging by what happens to her, Alison is not blamed for either of her awful behaviors. All of the men suffer something because of her, but by the end of the story she alone remains unscathed: no broken arm, no blistered bum, and no lips tainted with, well, you know what they were tainted with. It as if she is in the center of a golden circle, protected from all harm or danger. 

In fact, Alison is almost portrayed as a virtuous woman because she actually held off Nicholas's advances when he first approached her. Of course, that was a short-lived protest, but it was something.

If anyone is to blame for anything in this story, all the men are to blame for letting their sexual urges drive their actions. Criticizing seems a bit strong, but certainly Chaucer allows each of these men to suffer some kind of harm because he was lusting after a young, beautiful woman. In fact, he ironically uses Alison to be the source of the punishment Chaucer clearly believes each of these men deserve.

John deserves his punishment: a broken arm and wounded dignity and the ridicule of "[e]ach learned man" in town. Chaucer allows him to suffer these things at the hands, albeit indirectly, of his wife. Chaucer allows John to be punished by his wife in exactly the way John feared he would be punished: he is publicaly cuckolded.

Nicholas Handy is badly burned because of his own desire to taunt and ridicule Absalom; however, he got the idea from the married woman he spent the night with--Alison. Clearly Chaucer allows the young man to be punished and spares Alison, who commits virtually the same act (minus the flatulence, of course).

Absalom deserves punishment for his ridiculous and unproductive pursuit of a married woman, and Chaucer uses Alison to foully punish him. It is an unkind act, but clearly Chaucer believes the foolish boy deserves his awful punishment.

Alison, on the other hand, is unscathed.