Re: Question about Schedule A 5669
I don't think CIC would consider that misrepresentation without further investigation. Visa officers will also be aware that it is possible, and in some countries very common, to work under the table, so would not just take the company's word that your wife never worked there.
In any case, it would most likely not be considered material to the application. For a misrepresentation to lead to a refusal, it has to be something that could have lead to a mistaken decision. Your wife did not lie on the application, so I think she is safe.