Reverse Polarity Fuses Circuit Question

What makes the reverse polarity fuses special is there is circuitry in the converter designed to blow the fuses (via a short circuit)if the polarity is hooked up backwards. It can be as simple as a high power diode wired across the converter DC output, between the DC output and the fuses. Since the fuses are a higher capacity than the current the converter is capable of delivering, the only possible way to blow them should be hooking up the DC output backwards.