I've had a situation about a decade ago, where I was making an order (obviously unknowingly) with a DEA agent who seized my normal suppliers email for actual schedule III drugs (steroids), and was posing as the dealer and was still accepting orders. You can read about it here:
http://www.vpxsports.com/article-detail/drugs/the-rise-and-fall-of-steroid-super-board
Anyway, the order was for well over $2,000 worth of goods. After it became known what was going on, needless to say I was shitting in my pants. About a 6 weeks later I received about a 2 inch thick long legal document with all the names of the people whom ordered, what they ordered, and tons of other legal mumbo jumbo. The worst part (I suppose) was that there was a "warrant" for arrest for the name I used to order if I was to ever enter Louisiana. Louisiana was where the steroids I was ordering were being processed and shipped so I guess that was the extent of their jurisdiction, or care to pursue the little guys just making orders. They wanted the other suppliers, and the people raking in millions who ran the board, and the DEA eventually caught up with the guy in Thialand and extradited him to the USA.
This was about 10 years ago, so take what I say with a grain of salt, but I don't think the government has the time or resources to go after the small fish. If you are constantly ordering bulk amounts that's an entirely different story because I know of cases from the Silk Road where buyers WERE busted.
I've also had one other time where I had a package seized (steroids) and all I received was a customs letter asking if I would like to claim it, and how to contact them, blah blah blah. I just tossed the letter. In that "game" (the steroid order "game"), seizure letters are not common, but do happen. Anybody with any common sense just ignores the letter, and doesn't try to claim a scheduled drug.