I worked as a night auditor in a couple of hotels while in college, and I’ve never even heard a rumor of what you’re talking about. We never gave a scrap of information to a LEO unless it was directly related to a crime under active investigation (as in “we chased someone into room 204 and arrested them. Do you have their registration info?”).

As others have said, license plates were purely so that we didn’t accidentally tow guests’ vehicles and we could call someone who was blocking the fire lane.