I'm not sure about the laws in your locality (in the UK you have to have a licence from the UK Office of Fair Trading to offer consumer credit), but I would generally support banning anyone other than payday loan companies from selling very high interest loans - high interest loans from utility companies and landlords strikes me as an obscenity.

> What tends to happen is not that people go to the Mafia (traditionally they come to you!)

The mob definitely loans money at high-interest:

http://archive.boston.com/news/world/europe/articles/2009/03...

https://en.wikipedia.org/wiki/Loan_shark#Post-criminalizatio...