Justagame, with all due respect to those above, I have to disagree very strongly with their advice.
Junior days see a lot of recruiting activity. Your son should approach this like a job interview. Sure he can enjoy the game, and he should in fact come across as a likeable guy (which I'm sure he is). But if your son was invited to a junior day, in all likelihood someone the coaches trust has told those coaches your son is (a) good enough and (b)interested. He needs to make a good impression, and he needs to find out more about this school and this program so he can assess whether it is really the right place for him.
I have never seen junior days used to sell camps. Lots of things are done to sell camps, but if it's a junior day, they are spending money on your son. They don't do that for just anybody. Sure, there'll be more kids there than they can actually recruit, but then, not all of them will end up seeking offers, and surely not all of them will end up getting offers.
Before the event, think through questions you want answered. You will probably get a presentation of some sort from at least one of the coaches while there. If that doesn't answer your questions, ask any that remain. Asking polite but mature questions shows genuine interest and it shows you know what you are about. Questions can be about academics or baseball or the whole recruiting process (and how this particular program handles it, as they are all different in some way or another).
Also you will often get to hang around after the game and talk to players. You can ask them questions, too. Find one who's from your neck of the woods and strike up a conversation. These are guys who voluntarily chose to go there, so they can often tell you what it was that attracted them. And if you get negative vibes, that can tell you soemthing, too.
It is also fair to look for an opportunity to get the recruiting guy one on one and ask him, again directly but respectfully and politely, how he got interested in you and how you can pursue an offer. Let them know of your interest and that you do indeed want an offer. So many kids I think rule themselves out when they come in with low riding jeans and a slack jawed attitude, giving the impression they are not going to be the best teammates and maybe they don't really care anyway.
When I say "you" ask, I mean that for your son. You the parent have to hang back and let him do the talking. Your role at most is to help prepare him in advance to do that talking. You can help him to understand how an adult will react if he asks a question in what is potentially an offputting manner. (Many teenage boys, shall we say, are lacking in the social graces.) You can help him to deal with the adults who will be making decisions about his future. But once you're there, it has to be his show, not yours. The more you butt in, the worse will be the impression they have of your son as a young man. They want to know that he can fly on his own, so you have to let him show that he can.
Also bear in mind that if your son is good enough to have options, then this is the one time in his career that he will get to choose who his coaches will be. In high school, you get who you get. If he goes pro, he gets drafted, traded, etc., and he gets whoever they give him. This one time you get to choose. Get the information you want to be able to make that choice well.
If you have 3 schools you're most interested in, you don't need to push real hard for an offer right then and there. Just find out what their time table might be. When you think you know which school is your son's top choice, then let it be known that you'd like to be there and see if they will talk offer with you.
Many kids across the country already have deals done and many of those deals were struck right then and there during a junior day visit. This is a great opportunity and it should not be squandered lightly.
Remember that offers signed in the November NLI period are really only the paper confirmations of handshake deals made before then. You can make your deal now if you're ready. Or not, if you're not. But you don't have forever, so you need to be proactive so you can make your decision before your train leaves the station without you.
