Acting Rationally:

"Al" Capone was finally convicted for tax evasion. Were the police reacting on rationally?? To solve this puzzle, we must first look at how the performance of police forces is viewed: arresting and convicting the people who have committed a crime starting, because their success in getting criminals off the street is also a reasonable, if contentious, measure. Given that they didn't convict Capone for the murders he committed, they failed on that measure. More ever, they did get him off the street, so they succeeded in there aims. We must also look at that what the police knew and what they had experienced about the surrounding: they had experienced murders which they knew were undertaken by Capone, but they had not experienced any evidence which could convict Capone of the murders. More ever, they had evidence of tax evasion. As this got them off the street, we have to say they were acting rationally because they did.  

This answer is controversial, and highlights the basic purpose why we have to much worry hard about how to assess the rationality of an agent before we consider building it.