While there may be some coaches that use this as a money maker, there are plenty of other college coaches and recruiting coordinators that see the true benefit of an opportunity like this. Recruiting coordinators have databases with athletes that they think could be an asset to their program that are accumulated from seeing players at camps, showcases such as this and high school, summer and fall ball. The recruiting coordinator wants to get out and see these athletes as many times as you can to determine if and to what extent that player can help your program. Attending a game only allows the coach to see the player get 3-4 at bats and MAYBE 3-4 balls hit to them. If you go to a high school game, my experiences have been that you are lucky to leave with 3-4 guys who have the potential to copmete at the college level (I know some teams have more talent then others and have numerous players that could play at the college level, I am just saying on average 3-4). As I am sure you know, there is the chance that the athlete could have an "OFF" day where he goes 0-4 or does not have his normal command on the mound. As a coach, we want to come out and see our potential recruits as many times as we can. As I am sure you are finding out, there are a TON of showcases that are available for high school athletes to showcase their skill. It is a very daunting task as a coach to get out and see all of our recruits at all of the different showcases as well as find other talent that we have not already seen. I think that many college coaches would agree that it would be a huge convienence to have as many potential recruits (ones already on our database) at the same location as possible, along with players we have nto seen yet. Not only does this allow the recruiter to see the athlete again, but it also allows him to see how the athlete compares to other players that the coach is looking at. I do not want to speak for any other college coach out there, but I know how I, as a recruiting coordinator view this.
If you are uncertain whether the college coach truly is requesting the attendance of your son or whether he views it "as a money maker", possibly have your son send that coach an email introducing himself giving him a heads up on if he will be attending the showcase or not and what his plans are for the summer (ie. what other showcases he WILL be attending and where, what summer camps he will attend, and what summer team he will be playing for.
I might be completely wrong, but I am just giving my honest opinion. I hope this helped