I have only heard this document might be required at some embassies or may be you chose a wrong option. Though the one you mentioned looks fine to me i.e. Choosing "Yes" in the question you posted is the right answer in my opinion too. Since you are the legal guardian of your child.
Personally i also submitted this form, but not as part of my visa application. I actually am destined for Quebec where they require a separate document called CAQ (certificate of acceptance for Quebec). You have to get this when applying for work permit or study visa.
With my LMO, my employer had already gotten this for me "for work". However, for my son aged 6+ who is school going and i applied for an "open study permit" for him with CIC islamabad. This open study permit for Quebec requires a CAQ for study. I applied through there website separately and filled this same IMM5713 form to claim i am his guardian. Then latter my company's lawyer in Canada was able to collect a copy of that CAQ and sent it to me. Finally i submitted that CAQ along with my whole application to CIC.
So just fill it along and upload. At any rate it won't hurt if this is additional.
Personally i also submitted this form, but not as part of my visa application. I actually am destined for Quebec where they require a separate document called CAQ (certificate of acceptance for Quebec). You have to get this when applying for work permit or study visa.
With my LMO, my employer had already gotten this for me "for work". However, for my son aged 6+ who is school going and i applied for an "open study permit" for him with CIC islamabad. This open study permit for Quebec requires a CAQ for study. I applied through there website separately and filled this same IMM5713 form to claim i am his guardian. Then latter my company's lawyer in Canada was able to collect a copy of that CAQ and sent it to me. Finally i submitted that CAQ along with my whole application to CIC.
So just fill it along and upload. At any rate it won't hurt if this is additional.