As mentioned before Re-consideration is applicable when the applicant believe there is an error on the IRCC side. If they made an error by not submitting a document then they can't apply for re-consideration, Asking for re-consideration is asking the IRCC to look over the "current application" in their possession because they made an error in judgement. if a document is missing from the application that was submitted as is the case with this individual and he proceed in applying for re-consideration, the IRCC will not accept any new document and his application is rejected because his situation doesn't constitute re-consideration case, but rather a re-application and status restoration.
As you stated before, you're not an immigration lawyer so don't present your opinion as facts which can potentially mislead others and have serious implications on their status. Each individual case is different and is reviewed by different IRCC officers some will be very strict while other might be more relaxed
