Actually Duffy was encouraged/pressured to claim these allowances to bolster his claim of PEI residence and this was permitted by the rules. Furthermore he was advised that these claims were OK. I am not a Duffy fan but I always thought that he wasn't granted due process and that the criminal proceedings were a great waste of time. The judge agreed. 

Having said that the Senate still needs to look at how it compensates Senators for expenses, get Canadians to agree the rules are reasonable and then have a reasonable  administrative process independent of political considerations for disputes.