3 and 2,
A couple of specific reasons scouts appreciate what JoeMktg preaches is that area scouts will bring in their crosscheckers, special asst's, & scouting directors to see a kid. If they know that the player will be taking BP on the field vs. the cage, they'll want to make sure they're there to see it. If weather has washed the game out, they want to know before they haul their boss in a car 1+ hrs only to find the team isn't playing. It's not so much about marketing your son as it is about helping the scouts do their job, and to Joe's point, allowing as many eyes to observe in person what they'll be making a call on come June.
BP is extremely important as it may be the only pitches as well known prospect will see. Many scouts will watch a 1 for 1 night with two BB and a HBP. Scouts will video BP and will also observe the player shagging balls in the field, taking in and out, etc., as it may be the only real action they get to witness. Most area scouts are coming to multiple games, so this isn't as important for them as it is for the guys above them that they bring that may only get one or two chances in a season to see a kid firsthand.
Joe nails it. It's really about "help me help you" with the area scouts. They're trying to do their job and put as many of "their" prospects in front of their bosses so informed decisions can be made. The more you can do to help them, the more it will help you.