A lot of points made on this thread. Something that has not been brought up is this. Do you really want to go play for a coach that has not seen you actually play? Talk about a shot in the dark situation. He has never seen you play. You really have no idea if he actually thinks you can play for him or not. He is taking a chance on what he has heard. Your taking a chance that he is going to like what he sees once you arrive on campus.
When a coach recruites you based on his observations from watching you actually play what he is saying is "I saw you play and I am convinced that you can play for us. So I am going to offer you this amount of money to come here and play for us. Why? Because I saw you play and I believe your our guy."
Do you really want to go somewhere with all these questions surrounding you?
Sight unseen does happen. But its from someone that the staff trusts because their information has been spot on in the past and they are a very trusted source. But the vast majority of the time information from these sources is good enough to get them to come actually see you play. Not sign you sight unseen.