There's been some discussion about this, but I don't recall this being discussed. Or mayby I missed it. Anyway, here's my expierence.

Last week I had to mail out a parcel. It was worth a few dollars, so I mailed it priority and insured it for a few dollars. I asked our cute little postal clerk,"If my parcel is lost, destroyed or for some other reason dosn't reach it's destination,what proof do you need from me to make a claim?" She said,"did you have some kind of communication, such as an email,with the receiving party as to it's contents. I said yes,and I did, but not as to the "very" specific details. She said, "Then a copy of that email would be all the proof I would need." I then went home and sent the recipient another email and enclosed the following information:
1.Date and time mailed.
2.Post office and zip code it was mailed from.
3.Persons name it was sent to with address and zip code.
4.How much I insured it for.
5.Insurance conf. #.
6.A detailed discription of the contents and value of each item.

Not sure if this would make it any easier if you ever need to make a claim, but it wouldn't hurt.

Just some info,
Rick