1) I would just write DeductCreditInRatingGroup andalso log("blah") 2) Let it crash attitude is often misinterpreted. It means your system should be fault

1) I would just write DeductCreditInRatingGroup andalso log("blah") 2) Let it crash attitude is often misinterpreted. It means your system should be fault-tolerant in general, so you can focus on the happy case instead of trying to predict all humanly possible failure modes. If you _expect_ invalid input, then handle it properly.