We are a D3 program and our resources are limited so we take are open tryout seriously. I know at the big time programs they don't have to look for that one kid that they missed as much as we do. And yes our preferred walk-ons are guaranteed a fall spot unlike the true walk-ons who may last a day or so before they are released. With no scholarships the dynamics are different but most of the D1 coaches I know won't let a talented walk-on get away from them. It all comes down to communication between the coach and the PSA. I get hundreds of emails and texts from PSA's and someone on staff answers everyone of them. We add them to our database and then we ask for video and their coaches contact info and to fill out an online form. If they don't respond in a day or 2 we take them out of our database and move on. I know it's basically the same for the bigger programs as well because I get lots of local D1 coaches sending me guys info that won't cut it at their program but may be able to help us.