Just out of curiosity, what's the concern?
Are you worried that on a go-around, the pilot will fail to recognize the difference between 2400RPM and 2700RPM? Or are you worried that the pilot is unable to take their hand off the throttle? Or is it that the few seconds it takes to push in the blue knob is critical?
I am a firm believer that people eff up. Also, it is human nature to make mistakes. I discussed this with my primary CFI at one point and I decided to follow the guys on BT who said leave the mixture and prop alone till landing.
Here is a scenario that can easily happen, take a pilot and plane from the flat land, with the plane setup for summer heat in the flats. The pilot follows the suggested technique of prop and/or mixture left at cruise. Now land come in to land at a high altitude airport on a cold fall day and "abort" the landing as the wheels touch. Pilot grabs the wrong handle, and pushes the mixture forward, engine starts to flood and stumble, pilot pushes the throttle forward missing the prop lever, engine dies. I was lucky, I was still fast enough the second engine on the Aerostar carried me aloft long enough I could restart the second engine.
Now, I had only a few hours in the Aerostar at that point and I still had a CFII right seat with me and this was only a training flight simulating a go around.
In aviation, you often see two battling concepts. One mistake is all it takes and you are a statistic; however we then read NTSB reports and the Nall report and constantly talk about the accident chain. And how it was not just one mistake but a series of decisions that allowed that one mistake to become fatal. This is same type of issue; when you are in the airport vicinity this is a high workload environment, potentially high stress, and it is easy to miss something. Does not matter how many times you have done it, one day you will miss something.
The next argument I have heard is that I am proficient, and I have muscle memory to protect me, so I can easily push all three levers forward, or I can push prop, then mixture than throttle... Often their is an associated claim of muscle memory. However, most people fail to understand both how procedural memory (the correct term for muscle memory) and task saturation work in the human mind. procedural memory can only follow a route procedure that does not involve any conditional data points. If you need to make a decision, you are then utilizing declarative memory which requires active concentration. Where procedural memory helps with task saturation is the effective off loading of tasks to predefined routines that do not require conscious thought; a great example is walking. You can walk while deep in though about something else because the process is predefined and requires basically no thought beyond general direction.
With task saturation, the mind is unable to process additional information or manage additional tasks. Some via natural talent, others via training learn how to "prioritize" tasks while in this situation to then get the best outcome. When task saturated, tasks will often be missed/forgotten or done later. So when a pilot is faced with suddenly needing to make full power and the plane is low and slow with minimal energy, which pilot do you think is less likely to make a mistake? The pilot who already has his/her hand on the throttle and has a single lever to push, or the pilot has two or more levers and may have to consider the sequence of the levers? Which has more time to focus outside the window? Which has more time to react?
Tim