Is there a reason you are hung up on VB? A C# application, in my opinion, provides a nicer looking user interface, can interact with a relational database (to persist the data) and easily interact with the Arduino.
You could even have a web interface that accesses the same database, so from anywhere in the world, you could see who has what checked out, for how long, etc.
Assuming, of course, that people actually do the proper thing when removing a container.