I disagree. Basically it's saying that it's the stupid ones who underestimate the intelligence of people they try to cheat. The sort of incongruity that irony i

I disagree. Basically it's saying that it's the stupid ones who underestimate the intelligence of people they try to cheat. The sort of incongruity that irony is made of. If, say, only the worst martial artists picked fights with strangers, that would also be ironic.