The reality I guess is that this is a public forum, nothing more and nothing less. People come on here and in good faith based on their supposed experience of any immigration scenario share how supposedly something worked for them.
Also often some people find that at a border there is often inconsistency on what a CBSA officer will or will not do sometimes even down to the experience of an officer or simply they are too busy to action a request so they take the easy route to advise apply online only
Ultimately though it is down to an individual to crosscheck the facts/reality through official channels of anything said on this public forum before they move forward, especially if they might have even the slightest doubt.
I guess it might help if when people post advice in such a case that they include a disclaimer that anything that might be possible at the border would be at the discretion of CBSA, no way to predict any outcome so proceed at own risk.
Good luck anyway and hopefully you will get your situation resolved
