Especially when you do it with other folks money. These crooks that run these Ponzi Schemes put undeserving clients in dire straits when the whole thing falls flat - and it does. People have lost their life savings, homes, standards of living, and pride due to these 'businessmen' that usually skate away, smelling like a rose.
I feel that jail time should only be used in the most severe cases of criminal activity. It is a drain on taxpayer resources and does not have a proven record of reforming people. There are much better ways to punish someone without costing the government, and ultimately the taxpayers, money. In the case of a Ponzi scheme, the punishment should fit the crime. The person should be required to work to repay their victims in a supervised capacity.
The Ponzi scheme is a scam scheme promising high rates of return with little risk to investors. It is similar to a pyramid scheme in that both are based on using new investors' funds to pay the earlier backers. So, someone who uses this just makes people believe that they can be rich in couple simple steps. They should remember that free cheese can be only in a mousetrap.
Generally, I'm very much against the idea of Ponzi schemes but I don't like manditory sentencing, so I think it should continue to be treated on a case-by-case basis. I also think these type of laws would be hyprocritical as public institutions are allowed to operate in ways esssentially akin to Ponzi and the people continue to have no recourse over this.