Thanks Canada Post
Some guy on eBay bought that broken lens off me a few weeks ago. They paid promptly and everything seemed fine, so I boxed up the lens in the original box and shipped it to California.
I got an email today saying that they guy went and picked it up from the post office, only to find the box empty. So, somewhere along the way, somebody decided to help themselves.
Of course, since the lens was broken, I didn't add any extra insurance to it. That being said, I think there's at least $100 included by default. But now I have the hassle of trying to sort all this out and will probably have to refund at least part of the guy's money myself (which is also a pain since it's not in my paypal account anymore).
I'm waiting to get proof from his post office that the lens box was empty. Canada Post weighed the box up here and it was 3lbs, so I have my side covered at least.