Depends on what locale...the Guyana/Surinam thing, well, unless they received the package with Guyana or Surinam postage, I wouldn't believe anyone, since there is plenty of evidence that they are the same snake, just picked up from different lines on the map. But really doesn't matter with Guyana/Surinam BCC - just what look you are looking for.

Other locales, sure, I'd trust Jeff at Boaphile or Gus at Rio Bravo...and if I was looking for a specific locale boa, I'd be sure to do a ton of research on it first and would hope that my knowledge and the knowledge of fellow boa geeks could help ascertain the snake in question's origin.

More difficult, however, when you are speaking about Hog Island, since it's hard to know if the animal is "pure" or not...then it would have to come down to pure trust, and again, reputation would probably win out.