Dan, I’m sure you know this already but I have to hand over my passport at all international hotels, hostels, etc. However, I will never do that over the internet, only in person. I think that what you’re identifying is a very big lack of sophistication on the part of those folks who own the houses. Nobody is training them. The US State Department requires that keep our passport on our person for a reason. I once got into verbal fisticuffs with a Northern Vietnamese girl who was our guide when she insisted on giving my passport to the local police station overnight. Absolutely, postively NO. The Black Market is huge for our passports. She was in her early twenties, and after that she did her best to sabotage my trip. That’s all right- I can handle her. What’s a lot harder is handling stolen passport information.