Its funny that you mention this because during my "visit", veternary meds were also mentioned as a substance that you need a script for.
Pooches can cost alot of money. If you get a "visit" due to your dog's meds, this Country has more of a problem than we know. I think in that situation, I'd laugh.
The bad thing is with using USPS. United Stated Post Office has Federal as well as State jurisdiction, so if they don't like what you're doing, they can prosecute at the State or Federal level. I have never heard of this happening but...who knows. Its possible.
Scary...J~