Well, that's sorta the point. Is someone ever "100% sure," and even if so, for how long. As i noted in my post, i've been "100% sure of things" one minute as a 'consumer,' and then changed my mind or come across new 'intel' that was compelling enough to change my mind. I don't believe in absolutes like this. "100% sure" in the mind of an 18 year old being recruited/courted by multiple high-profile institutions/coaches, and friends, and being influenced by family, etc is not actually 100%.
I work in advertising/marketing, and my degree is in psychology, but no, i've never sold aluminum siding, if that would have validated my concern or opinion. This isn't like going to a Porsche dealership for a test drive when you only have Kia money.
Either way, i wonder if the staff feels the same way as you do, that entertaining a kid who may have already made up his mind is a complete waste of time and an 'insult.' Personally, i might welcome the opportunity to change a mind. And seeing as how we've been the beneficiary of players changing their minds even after commitments, or in transfers subsequently, i'd probably embrace an opportunity at any stage to strengthen relationships.