all it takes is staged buyers. but fortunately for silk road's sake it's too small and amateur to interest anyone with an agenda.
I'm sure law enforcement & the DEA didn't think that idea up, at least after a few senators called for the site to be 'shut down'.
http://www.reuters.com/article/2011/06/08/us-financial-bitcoins-idUSTRE7573T320110608What good can undercover ops do when all drops are made via mail using prepaid 'postage paid' envelopes?
Simply put: It's impossible to trace them. The origin of those letters can't be determined in any possible way. They are vacuum packed as well so dogs wont know what's inside either.
Mythbusters says dogs can still smell vacuum sealed drugs. I dunno.
It wouldn't be hard for the DEA to put a vendor on one of those sites. An 18 year old college kid could do it. That's means it would only take 50 full-time DEA agents.