There are some countries in the world (I recall Sweden, but I might be WRONG ) where buying a single Replica is not considered a felony, as long as it's for personal use and not advertised as something else.
Granted, if you buy crates of goods to re-sell its a different story.
I am under the impression that some if these packages that arrive in the US are indeed checked BUT, they end up being delivered anyway.
Are we sure there is a law in the US against "a single" replica purchase for collection purposes?
Specific Federal laws maybe?