Call me crazy, but wouldn't it be better to have the list only show items the users can check out?
Or if it isn't a list then disable the check out button.
I'm Jay from Tasmania (Australia) an experienced programmer 30+ years and 24 of them in and out of Access, specialising in speeding up slow databases. I'm keen to help out and get and give some assistance on those gnarly ones.
Likes: dachshunds, MX-5s and my sofa :D