Yes, that's a good point. Some of this depends on how the car is wired. On a street/strip car I'd run the red/white wire to the ignition key and use the key as the kill switch. I'd also probably run the heavy red & black wires to the battery and then 18 AWG red wire to the master cutoff switch. But as you pointed out, it depends on the ignition. My method would work with CNP, but might not work with other ignitions. So the answer is the old standby "it depends".