Hole in Windows XP Pro Certificate of Authenticity (COA)

[XylonJack]

Hello, I bought a retail copy of Windows XP Professional version on a second-hand website some time ago. It has not been opened, and there is a tamper proof label of an international trading company on the plastic package.
But I found a small hole in its certificate of authenticity (COA). I checked the unopened photos of Windows XP Professional Edition on eBay and some other second-hand websites, and found that there was also this small hole in their COA.
So what is the function of this small hole? I'm curious. Thank you.
This is my COA photo:


Edit: I found this article and according to this article the hole is designed to prevent piracy: https://support.dynabook.com/support/vi ... Id=1546033

[wustudio]

This is the norm.There is a hole in my copy too.

[KTRMAmbiance]

The same hole is also in the label pasted on older PCs that came with XP~7 pre-installed (where the product key is also written)

[Lucas Brooks]

The hole is there to prevent you from taking the label off and putting it onto another computer/box. It isn't really effective if you start peeling from all 4 sides but that'll distort the label a bit. It helps if you peel it with a blade and some rubbing alcohol.