There's some truth to that, but the honest reality of the "flying world" is that a fed could and would find a way to violate you if he wanted to. Simple as that. While there are steps you can take to alleviate some of this stress - nameably being compliant and trying to do the "right thing"- the giggle factor, "or common sense-ometer" needs to be consulted before flying. Why would you operate an airplane that "needs" cowl flaps without CHT? Additionally, when/if you get ramp checked, you need to be cautious of what you say. If Joe-Federale asks you why any of your equipment in your non-MEL equipped airplane is inoperative, it had better have "just broken during the approach." The proverbial "placarded inop and deactivated" is certainly not the final step for insuring regulatory compliance, sure, neither is TOMATOFLAMESSSSJFHDHEIKL! or whatever other acronym you use, that said, it is physically impossible for me to have a perfect knowledge of every aspect of CAR3, FAR23 in addition to company maintenance control programs, FAR 61, 91, 135, the AIM, the AFM/POH, the OpSpecs, OpsManual, the CRH/QRH, the myriad of local and distance procedures, as well as the various techniques and procedures required for safely flying the airplane from point A to point B. If, through the course of all of this, I miss something because I lack a superhuman capacity to retain every detail in unbearable minutia then if/when I get called on it, I'll chalk it up to inexperience - take a minute to learn, and hope the feds go easy on me. By and large this is why I'm on JC in the first place - not because of the networking available - and there is plentiful networking, but to hear the occasional tidbit like this and others, and hope it saves my butt - regardless of that, I don't particularly think that a frenetic worry over airworthiness is necessary when a determined fed can find something wrong with any airplane. Do your damndest to ensure the airplane is safe, beyond that, you're mostly in uncharted territory.
Frankly, I think that blasting off in an airplane that has cowl flaps but no operative or installed CHT is probably a bad idea to begin with. Again, common sense is what plays into this sort of thing. Common sense will typically keep you alive - the regs may or may not.