I think it's in case you decide to return the device per the 7-day rule on distant selling regulations. Mind you in order to do that you will have had to NOT opened the box.
- So I can imagine a lot of N900 customers are going to be doing that

Note that the 7-day rule is a "change of mind" thing meant to protect people from a rash "impulse buy".
If you open the box play with the item for a few days & then decide you don't want it, that's a different thing and the Vendor is entitled to impose conditions & charges (e.g. restock fee)