Five Popular Espionage Techniques

Nr 2:

"Live Drops

Live Drops are very similar to brush passes and dead drops. In a live drop, two agents make an exchange, but the exchange is hidden in plain sight.

This is because one of the agents is disguised as someone who commonly exchanges items with the general public.

For example, a man walks up to a hot dog vendor and purchases a hot dog. The man pays for the concession and leaves. However, the man is an agent and has just passed the hot dog vendor, his co-conspirator, a note mixed-in with his money or written on the actual bills.

Transactions such as these took place on city streets across the globe. There is nothing suspicious about someone buying food from a street vendor."

Source: http://www.topsecretwriters.com/2011/07/five-popular-espionage-techniques-of-the-former-soviet-union/