Son coached at the college level - ran or attended many college camps for different schools and entities. Yes, most are largely a vehicle to pay assistants and are run with minimal hope or intention of finding strong recruits. But there are also true prospect camps with specific invites to players the school wants to get on campus and get another look at. Yes, sometimes one is blended into the other.
If you don't have prior dialog with specific arrangements to spend time with someone on staff then don't have expectations of "being seen" at that event. There are exceptions. This is the norm.