From what I can tell...If someone's requested books frequently get "lost in mail" it can jeopardize their membership. It may not always be their fault, maybe they have a not-so-great mail-person.
This is from the Help docs:
If you are having a lot of books declared "Lost" en route to you:
- You should investigate this. Excessive unreceived books may jeopardize your membership.
- Numerous books sent separately but not arriving at your address implies that something is wrong with your mail delivery.
- Requestors are responsible for providing correct, dependable mailing information to senders.
- Check your address in your Account Settings, to be sure that it is correct.
- You can send a PM to the sender of any or all of the lost books, to ask if the book was mailed late, by any chance, as described above.
- Talk to your PO and mail carrier to see if the book might have been misdelivered to a neighbor.
- Consider using a PO box or alternate (ie, work) address until the matter is sorted out.