The check out function allows you to manage current attendance.
It does not cancel a reservation.
Lets say a member reserves the block for the family and checks in
Then Jane left to go get a pizza for the Family (see below) so I check her out.
NOTICE Attendance goes down to 10 (which is correct)
She is coming back, its her reservation.
Her leaving DOES NOT open a space in the reservations calendar
She come back with Pizza 15 minutes later, her reservations is still there.
And we can check her back in.
When we check Jane back in we come back to 11 in the attendance.