[jpalomaki]

You might be able work around this by striking a deal with the company handling the transit. If there's a pick up service, the guy doing the pickup could make a quick check on the goods and release the payment. This of course does not help for issues like selling pirated goods, which can't be detected on quick inspection.

My gut feeling is that large part of business comes from regular customers. I guess the probability to cheat goes significantly down on each subsequent trade.