Why? Obviously (or at least hopefully) the vendor is going to change their shipping method now, and LE knows nothing more about the vendor than what they could have discovered by ordering from them (the city they ship from). Also, it took me all of three minutes to look through the LSD listings and figure out it must be one of three vendors. This is more dangerous for the buyers because of the main reason that people use fake addresses. LE knows that some people use a fake number that is close to their real address, hoping the the mailman will recognize the mistake and put it in their box. LE can probably pretty easily figure out who the buyers of those returned envelopes are. If I was them, I'd clean house.