And, especially with a big chain, I assume that any information they collect (especially if they're required to collect it) gets put in a centralized database rather than depending on a paper copy being properly filed in a file cabinet someplace.

Somewhat OT but I was in Europe last month on a business trip. There's a knock on the door one evening. Imagine my surprise in discovering it's someone from the hotel who has come up with a few edible goodies for my birthday. On the one hand, it was a nice gesture. On the other, I was a bit taken aback. Where did they get that info?

I didn't really want to ask but a friend of mine later reminded me that they probably got it off my passport. I suppose this might have just been an informal process at this particular hotel. But I wouldn't be shocked to learn it was put in the chain's database.