IMHO, any pilot flying a twin who thinks he is immune to making this error is foolish. Having said that, shutting the wrong engine down is most likely NOT the pilot’s fault. The human factors and engineering in this area is abysmal. But in the end, it’s always the pilot’s fault.
Consider the number of aircraft that have caution lights stating something similar to “#1 ENGINE FAIL”. Yet the related emergency procedure typically contains considerable warning about the light's false activation. How about a warning panel directly in front of a pilot with the far left segment stating “FIRE”? I’ve heard many a pilot utter the left engine was on fire when responding to its illumination.
Actual emergencies involve failure modes and faults that combined, become confusing at best, and may not be covered in the flight manual (ask me about the loose DECU connector I experienced on a maintenance flight).
Many times the crew needs to evaluate multiple sources of data which are incomplete, inconsistent, conflicting or wrong. Often, multiple warnings with different color coding, location or associated horns and bells distract and tend to focus attention to the exclusion of other data.
I once flew a twin the military that had over 80 underlined emergency procedures. That’s purely ridiculous. I take the time to consult the checklist before accomplishing any critical procedure, especially when single pilot. You can easily "miss-remember" a step, the proper order or a crucial note. Obviously, if on fire, out-of-control or given no choice, youskip the checklist.
The golden rule of power lever/control manipulation is always to pause at idle, and confirm before proceeding. My current twin has a one-step memory item for single-engine emergency shutdown:
“ENG MAIN switch (affected engine) – IDLE, check then OFF.”
I break that down into at least 5 seperate steps!