TR...gotta lean on Buddy's side on this one. Schools like Marietta, N.C. Wesleyan, Trenton State, Ramapo, Wis-Osh Kosh, etc... get scouted by the pros each year, but for the most part, scouts tend to gravitate to high school or Div. I games if they have nothing on their daily plate.
Been an Astros associate for 11 years. The Astros chose the DIII kid in 2003 because he was exceptional. An exceptional player at a DIII school will attract scouts, but they probably knew about him from the prior summer leagues. Not because they happened upon him at a DIII game.
I think people get so caught up with "exposure" that they forget how much of a science scouting is nowadays. Most scouts have their schedule planned out a week or two in advance. They and the clubs they represent really do the ol' homework. If someone can play, no matter where they are going to college, the scouts will be out to see them. I would imagine that most scouts at DIII games are associates like me. The territorial boss asks them to take a look at a team and report back if they see anything interesting that would warrant another look. I think players and parents look for scouts, and if they don't see a radar gun or team gear, they assume they aren't there. My boss tells me to simply blend in with the crowd, and take in the game like an average fan. As soon as you are recognized as a scout, you can't do your job effectively. People want to talk to you, distract you, ask questions...not a good way to evaluate talent on the field.