@twoinanddone The college has to start a file at some point. My D visited colleges junior year and signed rosters. I assume they started a file or some notation of her visit. If a card filled out at a college fair triggers a file, why not an email or phone call from the student? Certainly my D was on the mailing list of many colleges by junior year.
I’m not suggesting this is a good method of showing interest, also not saying it’s not. I think if the student has a genuine reason to cold call/email the college, they should do so, regardless of whether the college tracks interest.