We understand your point. Our point is that the amount it 'adds to it' is minimal, effectively approaching zero.
Your original case, as stated, was this: "Why not as the sponsor and husband make a affidavit sworn in front of the rcmp that I take full legal responsibility of the visitors departure financial and medical? Then if they refuse launch a judicial review and go public !"
Okay. But we are contending that an affidavit (sworn in front of whomever) as compared to a simple letter has very little or zero effective influence on either the likelihood of refusal or the likelihood of success in a judicial review (which, repeat, does not mean the applicant is guaranteed approval of the TRV anyway).
And if so, the 'why not' in your question is "it costs money and time for precious little or no purpose whatsoever." Let the applicants decide, of course.
You say "it's your opinion, nothing more." Likewise - your point is an opinion.
And a small point: there are others here with some or even substantial experience, one of whom's experience is as a lawyer. Yes, a lawyer's opinion is still an opinion, but relevant experience and training means that the opinions of some are more valuable and likely to be correct than that of those without the experience and training.
[Side note: thanks for the information that RCMP officers can act as commissioners of oaths. The relevant point, however, is whether they provide this service upon request, as you seem to suggest. Have you ever tried this?
My belief is that they do not generally provide this as a service to the public (or possibly, if so, only in very rare situations such as isolated detachments and communities that may from time to time have no other available commissioners). The context in which an RCMP officer might need to have this power is in conducting criminal investigations, i.e. collecting statements from witnesses for the purposes of specific court proceedings. Possibly also in some civil proceedings but I don't know about that.
Please do try, though - go to an RCMP detachment and ask, or call them.]