I was vacationing on the east coast last year, driving around in a rental car. Lady at one of the hotel’s insisted on having my license plate number: it is a rental, I don’t know it, I don’t care to know it, and you don’t need to know it.
But it was for my own protection. No it isn’t. Really. It isn’t. She tried to get me to provide it several times when I happened past the entrance. No.
FWIW, I tell them I can’t remember. When they object, I say, “Look, if it’s that important to you, walk outside and write it down.” That usually ends the discussion.