Spirit of the Rule is waayyy to subjective. I mean how do you define that in a gym where one team chants "We got spirit yes we do We got spirit how 'bout you"? Aren't they inferring that only ONE side has spirit or that one side has more spirit than the other? Very subjective!
If you need to CYA, it is better to be able to point to a section in the rule book then to say I was officiating by "the spirit of the rule". Or you can just say you blew the call which is also affective in small doses!!