When you're shipping anything with a courier company, you have to be sure that you follow some basic rules that are going to be set out by the courier as terms of receiving their service. Otherwise, you can run into a lot of problems during the course of a delivery. Any courier PA based should be able to provide you with a written copy of these, or at least point you towards a listing of them online. The most significant portion of any regulations they have are going to concern the packing of shipments for transport.
Most couriers have fairly strict guidelines when it comes to the preparation of a package for shipping. The reason for this is that if a package isn't packed correctly, it can very easily be damaged. This results in a lot of insurance claims, which are costly, and can drive up the insurance rates of the courier. It can also damage their reputation if word gets around about too many damaged packages. They reduce the occurrence of this by making sure that all customers pack things according to the guidelines.
It's not difficult to pack something that sticks to the guidelines that your courier gives you, as most of the items on the list are going to be easy, and in your best interest anyway. This includes things like making sure that there is no empty air in a package so that breakables can't rattle around, and that anything which might spill or leak is sealed up. Usually, there are also a few guidelines concerning proper package labeling, so that your package doesn't go astray thanks to incorrect labeling.
If you don't follow these guidelines, you could potentially get yourself into a situation that you'd probably much rather avoid. The worst of these is if your package gets damaged and you haven't followed them, you may have violated the terms of the insurance. You usually have to show the packaging when making an insurance claim, and if you clearly packed something wrong, you may not get compensated for it.
The next problem that you have to worry about is that if you pack something incorrectly, the courier may add a fee to your shipment. For example, a common fee is assessed when customers label their packages incorrectly, especially if that results in a delivery to the wrong address. Keep money in your pocket by just taking a minute to check your courier's guidelines.