Government sends old lady to prison for running a profitable spa

A (70 year old) Houston woman faces up to five years in prison after she pled guilty Tuesday to knowingly employing prostitutes at her Longmont spa. 

http://www.rockymountainnews.com/news/2008/dec/17/longmont-spa-owner-pleads-guilty-hiring-prostitute/ 

Yet another reason why we should legalize prostitution, who really wants to see an old lady in prison?

Somehow I don’t see a 70 year old woman as a threat to society. Isn’t that what prison is supposed to be for? To take those who pose a danger to society off the streets. If prison is solely about punishment, can we not come up with a more humane way of punishing those who pose no threat to society?