Credit card imprint

How common or uncommon is it for a hotel to reqire a credit card imprint from every guest, especially those playing cash, *especially* if they're smokers?

Earlier this evening, I got a walkin who got 2 nights and when I asked for a credit card for an imprint, she refused, saying she'd rather stay somewhere else rather than give a credit card for me to get an imprint of.

Her reason? She would only say "I've never had to give a card for an imprint before"

I think she was full of it and there was some reason she didn't wanna tell me.