I recall being required to hand over my credit card on 2 occasions. The first time was at an HGI in Las Vegas. When I politely questioned the requirement I was told they were allowed to require the card due to issues with fraud. After the stay I confirmed with Hilton that this was allowed. The second time I ran into this (can't remember the hotel) I went along with it given the location.

So I assume, to answer your question, that in at least some situations the official policy allows it.