As things are right now, you can certainly add insurance on any package you are sending. I would hope that this would remain optional because the cost of postage and dc#'s are already an issue for some swappers. I know it would only be a little extra, but after the cost of supplies and the required postage, it just may be too much for some.
Balkandina - my son is about the same age as most of the people on this site, so there are a few of us old folks around!! And more than once I have seen people on this site come up with something they think is new that is actually something we used to do when I was a teenager, so the loop goes round and round!!