Why is a receipt important?

[CocheseUGA]

I was looking through past 360 threads, and something that came up was 'receipt included.' Why is this important, so you can return it to the store, or what? I ask because I have a supplier that I am buying from, and I'll be offering up some bundled and non-bundled Premiums over the next several months. With a supplier, I won't have any type of receipts.

Also, does anyone know if you need a store receipt to validate an Ipod warranty?

[encendido5]

I assume it's for warranty purposes. It's also easier for the buyer to return or exchange it to the store in case something goes wrong with it.