I agree with everyone else who says to check in and NOT check out. It happens automatically the next day.

Do us all a favor and ask for the crappiest room upon check-in. Save the 'nicer' rooms for others who are checking in after you and will actually be staying the night.

You're gonna have to pay for the night either way and the only way to get credit for it is to check-in in person. So you might as well do it if it's not too far out of the way.

-RM