Keyword being: "with intent to deceive", he's not trying to get a leg up by falsifying his information, I personally switched my NOC after ITA, because I found one that matched my duties and responsibilities better, in a completely different section, still got PPR. Bottom line is they know that their system is not infallible, and most reasonable officers will see that there could be overlap or missing responsibilities from the chosen NOC.@MajorGrom @mushymush
I don't know how the IRCC officers make the decision concerning the NOC, but chosing a NOC that you cannot back up with a reference letter stating at least some of the roles listed there is clearly a misrepresentation.
What is misrepresentation :
A misrepresentation is a false or misleading statement or a material omission which renders other statements misleading, with intent to deceive.
Since IRCC has clearly set the NOCs eligible to apply through Express Entry, chosing one you cannot match, is therefore not just a mistake.
Ontario has a whole nomination program that is based on NOC selection, so I would say they play a pretty important role in the application process.
I would advise to do a careful research when chosing the NOC, which you would have plenty of time after the ITA to consider it.
Let's just hope MushyMush's application lands on the desk of the most reasonable officers they have.