They could indeed "do something" to your buddy. He would be guilty of violating the Lacey Act by shipping a protected animal across state lines in violation of game laws. That is a felony. He's lucky the authorities let him off with a warning.

i NEVER ship any of my baby spotties into states in which they are native unless the customer provides me with a copy of a valid and current state permit.
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Brad Chambers
WWW.HCU-TX.ORG

"Some things are flat impossible-until they're done."
Robert A. Heinlein