As I have posted, I lost the battery door on my Droid like many others.
Matt a moderator on the Motorola Owners' Forum acknowledged the following:
"A very small percentage of the doors are a the low end of our specifications. If you are having a problem with your door falling off, contact our call center. Use the link on our forum home page that says "Contact Us" and you can either call or chat or e-mail. We'll send you a new one.
Sorry for the problem."
Mine is on its way via FedEx -- Motorola is paying for the door and delivery.
Here is the link: https://www.motorola.com/feedback.jsp