Sadly, it is an objectively risky suggestion in the case of POHs and AFMs that enshrine the sort of hogwash repeated in the AWB.
The primary causes of spark plug insulator cracking?
(1) LAMEs dropping plugs then surreptitiously refitting rather than replacing them.
(2) Manufacturing defects.
To the extent that the way in which an engine is run may cause insulator cracking, (3) would be running the engine RICH OF PEAK, but not far enough rich of peak.
But an evidence-based regulatory system should be run on the basis of folklore. It must be the fault of pilots running engines LOP. FFS.
