[mothered]

Packages are weighed on consignment, so If you're using (for example) the missing Item method, you need to be selective by opting for a very lightweight Item.

Most companies liaise with the carrier. For Instance, If the package was dispatched from their warehouse at 4Kg and was received (by you) at the very same weight, but you're claiming a 1Kg Item was missing, then your SE will fail.