Isn't that why bit coins are pooled some places, so you really can't tell who used the money for what? Like I deposit 100 bitcoins into bitcoinebay and when I spend it it's just someone else's random bitcoin so it doesn't actually lead back to me?
The only way I could see this is with how few jobs are available some places and that drug dealers, movers, etc wouldn't be able to find work. That's probably a pretty high amount of people involved in illegal businesses that wouldn't be able to make money otherwise.
South Pole, google operation High Jump and the conspiracy theories about it. Also Wernher von Braun went down there to get moon rocks. He actually did, but that's ammo for the we never went to the moon people.
Bad analogy, since I can't actually see or hear your phone communication without assistance or breaking the law the police should need a warrant. Just like you mailing an envelope, if I go into your mail or the recipients mail and open it I have broken the law.