I've been away from the board for several years but a PM from someone who's son is considering the school my 2016 attended brought me back. Nice to see so many familiar members still helping parents with this crazy process!
I'll add our experience to this thread for what it's worth. In Aug of 2015 we were in the same boat as has been described by several posters here. Locked in on D3, hoping to use baseball to get him into a HA school - not top HA but schools like the mid-level Centennial Conf schools and others in the northeast. He had lots of marginal contact, emails, invites to prospect camps, etc. but nothing resembling an offer.
He attended Headfirst on LI early August and killed it (he's a RHP). Had interest from a HC from a HA school in Wisc right there after he pitched (which we knew nothing about until after) and then nothing. Crickets.
We were on vacation later in Aug when the emails began coming in from coaches that had seen him at Headfirst. Those emails were offers to visit campus, meet with the coaches, attend classes, stay over with the team, etc. None of those offers included asks for him to attend their prospect camp. All the visits were set in Sept/Oct. While he was receiving the invites to visit XXX schools - he continued to receive emails and offers from other schools to attend their prospect camps in the Fall. He also played for a Fall team in hopes of attracting some attention (we had already signed up and paid for it when the interest started coming in) which was a waste of time and money.
He ended up applying ED to the first school we "officially" visited which had been on his list and we all agreed seemed like a good fit for him (we had seen many other schools unofficially prior to that). The weekend he visited his school - a Centennial Conf school he had targeted - they also had their prospect camp. None of their official recruits who applied ED and were admitted attended that prospect camp.
All of that class had PG profiles and updated their profile to show that that had committed to that school after the ED decisions went out. As did the commits of most of the other D3 schools he looked at or recruited him post Headfirst - admittedly I spent way too much time looking at that stuff back then. You won't get a true picture of D3 commits until after the early decision word goes out later on.
Son had multiple HS and Summer team teammates who went through same process with schools like Trinity (CT), Emory, Union, Skidmore and others that I'm blanking on now but all were invited to campus for visit to meet with coaches and stay over. All sent transcripts for pre-screen prior to visit - and all received an "offer" of coaches help through admissions if they applied ED at that meeting - with the usual disclaimer that nothing was guaranteed with admissions.
At this stage I would not have son attend a prospect camp at a single school (without other schools attending) unless he had detailed conversations with that coaching staff and they said some of the things noted above - like we need the whole staff to see you, etc. Don't get me wrong - we were looking at the same sort of camps mid-Aug of 2015 before he received offers to visit schools but I don't think the coaches are expecting to pull a lot of that year's prospects from those camps.
I can recall multiple posts back when I was here every day, all day about emails from coaches and how you can tell the difference immediately between an offer to attend camp - and an offer from a coach that is interested. They don't beat around the bush, you don't need to read between the lines - they spell out clearly that they saw you play at XXX, they liked XXX about your game and they want you to come see the campus and meet the coaches.
Happy to answer any questions if I can. I wish everyone luck with the process. I can tell you that my 2020 does not play baseball and isn't trying to play sports in college and the process is just as crazy for non-athletes. We've visited multiple top tier schools in the northeast this summer and the info sessions/tours are at capacity multiple times a day with people from all over the world coming in (paying $10k more than these schools cost in 2016). BU had 65,000 applications last year for ~3000 spots.