all of the hotels in the EU that I've stayed at always ask to see my passport.... not really a problem with me and besides, I believe they have laws that requires it.

however, there are some hotels where the front desk clerk will insist that you let them keep your US passport for the duration of the stay. (that very large luxury hotel in Hamburg, for example) do they have the legal right to do this? I'm not the type to complain, so I did hand over my passport and got it back at check-out. What scares me is that they don't keep the passports in a safe or even a locked drawer. I was talking to the concierge at the counter one morning when I noticed all the passports were in a plastic containe sitting behind the counter. If I stretched my hand out while the concierge wasn't looking, I could have grabbed a bunch of those passports.