@orcrist all due respect you sound a bit paranoid.
I'm a New Zealander. Every time I have stayed in a Backpacker hostel in Germany or Austria they have asked to see my passport and made a note of its number. Sometimes in the past they "held" my other government-issued identification instead but always sighted the passport.
If you don't believe me, that's fine.
But I'm not interested in continuing this conversation. I find it deeply strange.