Seeds that get discovered in transit into the country are usually just confiscated, and then a letter is sent to the recipient saying the seeds have been confiscated, and that is the end of it. The older threads here about it are gone but if you search for it online you can find one of the form letters people get. From what I have read seeds discovered in the mail are simply destroyed and that is the end of it, they don't come after the people that had ordered the seeds. This is because there is obviously a large amount of seeds being sent in the mail and the government can't track everyone that orders seeds. Why would they? If there are hundreds of seed orders being sent into the US every day, why would they look into that instead of actual terrorism and real threats?
THG is right on