With a one week lead time I don't expect we will be anywhere near sold out. Alan is offering free Vortex stuff and there still isn't that much demand for distance opportunities. I remember a thread on INGO once where folks were going to have an open carry rally on the circle. It got something like 200 replies and 150 "be there"s. In the end five people showed up.
Like many cultures, the gun culture has a lot of....vocality. Realistically, though, few people want to commit to several things that can be exposed by an event like this (unknown environments and people, lack of ability (either skill or physical ability to experience it, lack of fitness [yes I know it's not grueling or anything but some folk just don't want to be faced with carrying your rifle/ammo/water all day], or poor self-awareness). I comisurate with those people. I hate new things. I hate humidity. I hate being faced with the potential of my own failures.
Some folks out there want to make themselves better. That's who I want. I've done too much of this to worry about numbers. I used to be part of an org that demanded numbers but had no understanding of what numbers meant. I'm over that. I want to do clinics for people that are trying to make themselves better and I don't care if it's two or five or fifty. Just be into it and you'll be all right with me.
Or could it be that with short notice people didn't have time to plan? Get ammo ready (buy, save up $$$ or reload), get permission from the boss (yeah we all know the wife rules), reschedule previous commitments, make range time to confirm zero (heck find a range where you can shoot centerfire), etc, etc.
Not so much different than RSVPs to a party, you are lucky if 50% of yes shows up.