Do me a favor call USPS ask them if you have a click and ship account and you are unsure of the weight what you should do. -I was told by a USPS worker to label it as one pound and corrections could be billed to my account since I have a credit card on file with them. The monsoon was sent and JeromyD has a photo of an empty box? Great I could as easily have my son take the geckos out of the deli cups and show a photo of an empty box with deli cups. FYI still no call from my son saying geckos are there.
For me, I guess the video isn't that important. We have to assume he shipped what he said, and it was packed well. If in fact, the gecko's aren't what you expected, then it's kind of a separate matter I'd think. Still doesn't make shipping an empty box right.
I would be interested in seeing your receipt that you put the initial purchase of the shipment on an "account". That might give a small amount of validity to the weight discrepancy, however, even if you did, I would still likely point the finger at you for not having the correct weight, on that box.
I guess it's on you, to prove that the box didn't weigh 1lb. I don't believe there's a way to do that. One of those things you should probably make sure of when shipping in the future.