Yes, this is a prospect camp. Like most others the vast majority of the slots will be filled by first come first serve players of dillusional parents willing to drop cash on any and everything. If you are on Duke's rader you have already heard from Duke (through your HS and/or Club) and missing this event will not get you crossed off their list. If you are not on Duke's rader this is not the sort of event that will get you there. This is a glorified summer camp with the difference as already noted being that it is only one day and takes place in the fall. This is not unique to Duke. Prospect Camps are only worthwhile if you are on the school's 20-30 player short list. If you are on the list going to prospect camp is optional especially if it conflicts with club or school play.
yes and no - I know of two kids that were not on anybody's watch list and went to one of these (one was my son) without having been contacted first and wound up getting recruited by those schools. this is an excellent way to get on that list if you are not on it. An "unknown" is not going to get recruited because of a one day event like this but if they perform well and stand out they certainly can become a "known". I don't think that Duke has a 20-30 kid watch list that is impenetrable by a HS freshman at this point.
