Rent fraud and punishment
A common issue I had to deal with was the rent being paid to the tenant to give to the landlord, (under current rules this is the established norm). The tenant would not pay the rent, the landlords could sometimes by the time it had run through all the procedures be 4-5 months behind on rent.
Once discovered all that happened was the tenant moved out / or had already done a midnight flit, the Landlord was left to recover the money from the tenant (near impossible), and the tenant well they went unpunished, in fact they could immediately apply for housing benfit again. Some people did this quite consitently.
No action was ever taken against them in the year and a half or so that I worked in the benefits office, they didnt even adjust their income levels with the rent they pocketed for their claims.
Likewise overpayment frauds, and other benefit frauds were often treated with mild indifference and if they were made to be paid back then since the person was usually on benefits then the payment amount is fixed and works out somewhere in the region of a £3- 5 max. (That would be you repaying two frauds back btw).
You want to stop fraud easy punish them, if thats the only treatment you are going to get for defrauding the system then what do you expect?