How does National Electrical Code section 300.4 (D) apply in this situation?
I’m not a NEC attorney nor did I stay in that fancy motel last night but one of the “intents” of “the rules” is to reduce the number of material casualties suffered during construction.  A sheetrock craftsman won’t use 16-penny nails to mount sheetrock and is highly unlikely to miss the studs or furring strip with a standard drywall nail or screw, hence the 1 1/4” (and metal plates) rules.   Mr. Homeowner, while installing a shelving unit for knickknacks might use a 16-penny nail but I’m confident wiring a house with EMT would turn expensive in a hurry.