I go to DSM now and then. I usually have an early AM return flight. Their counter does not open until 7 or 8 on Sundays. There is no one to check in a car. They have a drop box for the keys. Never had a problem. On the other hand I dropped off a car at the Sixt station at the Madrid airport. They said they would send me a receipt. I got it in the mail two months later(came by ship-I didn't know mail from outside the US didn't arrive on anything but airplanes any more)