I think using the term fraud is a bit unfair. OP and the airline agreed to a contract with specific terms and conditions, including penalties for violation of the hidden city clause. Depending on how it's written, the airline may choose to enforce those penalties, if the OP violates that rule. The penalty could include forfeiture of ff account, monetary penalties, or ban on future services. If the OP wants to take that risk, it's OP's choice to make. I would not expect the airline to be sympathetic to your plight, and if irrops occur, OP would be in an even worse situation.