I am a hobbyist who has shipped maybe 20 or so packages of coral, and bought a few myself. I have the same DOA "policy" that is mentioned, mainly because it's what everyone else had so I figured there was good reason. I've never actually had any issue with coral in shipping or with customers trying to get any sort of refund. Though I still had that sort of DOA written in my posts, I still would have worked with anyone who did have an issue and likely would have offered up a refund if the circumstances warranted it, or offered to send a replacement shipment at the cost of shipping only ( another way of sharing the burden of shipping delays).
Just because people have that written up as a policy, doesn't mean they are trying to screw anyone over. They are just trying to cover their butt's. For many of us, this is a hobby after all and I spend enough money on it already. Last thing I need is to worry about having to pay $50-60 in shipping plus lose whatever frags someone may have bought because of a screw-up by Fedex or UPS. That would deter many hobbyists from ever trying to ship I think. I think it also makes it harder for someone to try to find some sort of loophole they could abuse to screw over the seller somehow. Not sure exactly how, but maybe a shipment is slightly delayed, and they see the frags aren't as big or vibrant as they thought, so they make sure the frags are dead and then claim it was due to a shipping delay. I know that sounds like a stretch and I don't know anyone that would do anything like that, but there are always people out there looking to abuse the system for their own gain. I see having that verbiage for DOA as a way to protect yourself from that kind of situation more so than as a way of backing out of any responsibility.
I was thrown off at first when I read some DOA policies from hobbyists, but after thinking about it there is alot of risk from both seller and buyer, so I get it. It's kind of just one of those fine print things that seems bad, but is rarely used.