I'm glad to see so many people excited to participate in these, that we can do them often! I always got sad when I saw all these super awesome corals that I couldn't afford alone being set up for group grow outs in other states.
The idea of them is to "go big or go home" because of what javiersito91 said above. Most people can afford the $100 frag... but a $1000 frag... not so much. This allows multiple people in one area to get one for an affordable price.
That's not saying that if you want to set up a less expensive one, go for it! Anyone can set them up and for whatever type of coral, chalices, acans, SPS, zoas. It could be for a kill pack you can put together or for just one super expensive frag.
Regarding insurance - everyone participating knows that it is an "at your own risk." That goes to the person you select for grow out, to tank conditions, and to the unfortunate unseen event. You cannot hold the person responsible or expect them to make a claim on their homeowners insurance. Make sure you select (or participate with) a trustworthy person who knows how to care and frag the coral intended for grow out!
That being said, I can host the first one if everyone wants (thanks for the kind words on my tank). I'm thinking a high end chalices (and/or acans/micros thrown in for fun) pack. I'm flexible and can put together anything from $1000 to $2000 for a super crazy pack. Or I could also just do that one sexy chalice I first posted.... the one that is $1500 a frag (I've seen frags of it and even the frags are stunning).