Just to add my 2 cents worth. I received my Fritzbox on Monday 9th (I assume this is from the new shipment as it came in a proper box - all be it missing a manual and 2 x rj11-rj45 adaptors, but don't really need these).
There wasn't a sign of a post-it or password/ username, etc anywhere on or in the box. So it may be an unfortunate 'one off' you have experienced?
On a separate note, my only frustration is that I'm now waiting on Chorus to install a new VDSL card into a cabinet (at least that is what I think I'm waiting for) and then a get splitter installed before I can get VDSL up and running. On a more positive note, Snap quickly put me on the ADSL plan (switched from Orcon) without any glitches and I'm getting better ADSL connection speeds already (Orcon best 11.91 Snap best so far 12.71).