This has always been an issue for us as well. We always close the library to circulations two weeks before the end of the year for students. (Teachers can keep things out longer, especially if they are doing end of year projects with their classes but most of them try to get everything in.) We used to tell students that they could not participate in Field Day if all their books weren't in or paid for and we had 100% compliance the years we were allowed to do that. Then we were told we couldn't do that anymore so we withheld report cards but now are no longer allowed to do that either. I do give out Golden Shelf Elf award certificates to the classes that get all their books in by the ceiling date and we do pretty well with that. I also announce the classes over the intercom at the end of each day and we send overdue notices and have teachers try to assist us in retrieving the books. In the end, we always have a some students who never return or pay for books by the end of the year which is disappointing but our hands are tied. At any rate, there is no way we can extend the ceiling date any closer to the end of the year. I do continue to have classes until 1 week before school ends but then we do have to concentrate on inventory and organizing the library before the last day so we close down completely the last week of school.
UGH!! The worst time of the year for me is trying to collect outstanding books!
I too have all books due 2 weeks before school ends and then I spend ALL of the next few weeks gathering the books. I have two libraries which logistically makes the collection challenging. I am constantly running back and forth checking who still has books out so I am not calling and emailing families who have already returned.
Our policy is to hold report cards until a family makes contact with the principal to plead their case. I am not always aware of who is on free and reduced lunch or who is in a special circumstance but the principal does. He then determines the "payment" options~whether to waive it, partial payments and we have even had struggling families "work" off their lost books with school jobs.
In any case, I would not want to do any circulation closer to the end of the year. Book round-up is already a BIG job in the time we already have put aside.
Good luck my colleagues!
Elaine