Found a film or strip stuck inside the back cover of Lenovo K3 Note I have a a phone Lenovo K3 Note. I noticed something paper like stuck on the back cover of the phone. It is like a film, found on clothes of some stores so that no one can steal them. But what its use on my phone, I couldn't understand. These are the images of the sticker:

Stuck on the cover



Upper side


Was stuck like this


Do anyone know why it is put there, I am little suspicious about it.
According to people at https://www.reddit.com/r/lenovok3note/comments/3eousk/could_the_lenovo_k3_note_be_optimised_for/ it's used for shielding the Sim cards. 

I'd be surprised, and posit it is actually an anti-theft or tracking RFID sticker - possibly bigger then typical as it needs to work through more packaging?