hulahoop said:
Honestly I think the decider between being cancelled and not is largely down to how bloody minded and/or how much of a bad day the officer is having.
I spoke off the record to a Canadian Immigration Lawyer who has 25+ years of experience doing PR and WP applications and he told me the most important thing he learned about the process and CIC over the years is that "If they like you, you have a much better chance of success."
He explained that he seen in case after case where the applicant wrote a cover letter/letter of explanation and appealed to the agents kind side that small things were overlooked and agents would even go out of their way to allow an application to be approved (for example, holding onto it until sufficient time had passed that an issue no longer was an issue). On the flip side he told me that he had seen cases where an applicant was rude in a letter and was punished for it. He gave an example of a WP being denied because the applicant was incomplete (and he was) but instead of denying it right away the agent held onto it until it was too late to submit a second application, because the applicant had tried to trick the agent.
The moral of the story...be polite and use what you can to appeal to the good nature of the CIC agent. It won't fill a hole in your application, but it might be the difference between a request for additional document or an automatic rejection. The CIC agent, while working within the rules, still has some flexibility to make a judgement call AND after all they are human.