Perhaps, or they just don't do it again. Not all people in jail go back. Generalising things like you have here is not helping anyones understanding on the issue
No, I wasn't especially precise but it's reasonable to assume that I'm rational enough to understand that not everybody that's released from jail re-offends, but it's fairly common: 60% for the US and 50% for the UK. [1] Likewise, sometimes governments fix their own wagon when they get caught doing some shady shit; often they don't.
[1] http://en.wikipedia.org/wiki/Recidivism#Recidivism_rates