It's impossible to keep up with all the scammers out there. There are new ones cropping up everyday. Like someone else also said, good sources can turn out to be scammers too. It's the nature of the game and everyone is susceptible to getting scammed including the Mods on this board.
I mean think about it for a second. This whole set up is a scammer’s paradise. Most of the sources you deal with you never meet or speak to over the phone. Money is exchanged via Western Union or Moneygram to some random person that usually requires that you ask a "test" question so he doesn't have to sign for it. You never know who you're dealing with. If it works out then great but everyone who's been in this game for any length of time will get or has been scammed. It's the nature of the beast. As a general rule of thumb, don't order what you can't afford to lose if it came to it and take the necessary precautions like multiple reference checks with well known Mods and Vets.