For the most part this is how I want it. I don't want the out of stock items to disappear from the dropdown. I prefer they stay in the dropdown with the out of stock text.

The perfect scenerio would be to have a pop up warning come up when someone tries to add a out of stock item, but I'll settle for the warning in the cart for now. Most people won't add a item that clearly states out of stock next to it(i hope)