Good packaging consists of multiple layers of vacuum seal and some kind of visual barrier. Fake names, vacant addresses, no return address, trying to mask smells with coffee/foods, etc. are all generally thought to be criteria for 'flagging' a package for more careful review (drug dogs, x-ray machines).
I've also purchased Zopiclone and Valium through Silk Road which has been shipped from the U.S. without issues (Hyperdontia, so with frequent toothache I need to know I can get to sleep at night so that I can work the next day, and I've had better experiences with the vendors on SR than I have with doctors and dentists.)
FYI if you have an abcess then you should really get it seen to!
http://worldental.org/teeth/abscessed-tooth-complications-an...
I went to my GP asking for a single Ambien (Zolpidem) to help me sleep on a long haul flight and they said no as it 'could cause dependency'. So I bought 60 over the counter with no prescription in Thailand.
I don't have a fear of dentists, I think spending money on solving pain issues is the best money one can spend. And I use a private dentist rather than NHS (since every NHS dentist near my home does not seem to be taking new patients.) – It's not an abscess that I have, I seem to sprout new teeth frequently, I'm on my third and fourth set of adult teeth (different teeth in their own different generations), and they keep coming, and as they're pushing through it causes a lot of pain, which is manageable apart from a pain perspective, but I don't get much sleep whilst waiting for an appointment. Zopiclone helps with that, but it's not easily obtainable despite the condition being on medical record.
The vast majority do seem to make it through though although some odd things do happen, some packages appear to have been held up in customs for literally years before they're released, it's not unusual to hear stories of people receiving orders that they already received (because they were shipped a second time and those got through) a couple of years after the initial order. You've got to suspect that might be an attempt to damage the companies selling them economically by making them re-send to destroy their margins.
But the trade still thrives, not just for the US but also for high tax countries ordering from abroad is a much cheaper and practical option.
Just the other day I ordered £0.99 worth of self-adhesive hooks on ebay, with free shipping from Hong Kong.
It's hard to say whether the parcel passed an inspection that left no marks, or whether it just wasn't inspected.