Possibly there was an error and they might charge ur cc by mistake.

I had this rental with hertz back in 2019 where the agent pre authorized someone else’s cc at the exit gate, when I returned the car I noticed the weird cc number on the receipt but the return agent didn’t really care and told me to call CS. I called in, hertz rep said they will charge my cc on file but they never did, I sent another webform to follow up but never got a reply, so it was a free rental at the end and hopefully the cc holder noticed it and pursued further with hertz.