Truly breeders should do their very best to ensure the buyer knows what he or she is buying. I've had a female sold to me as one thing and I'm pretty sure now she was likely of mixed heritage. She was still a fabulous animal. But she was not what I paid for.
That said, I dont really believe most captive animals can be 100% guaranteed truly purely this or that, since I doubt many (there are exceptions of course) breeders know the lineage back more than a few generations, and probably the original imports were somewhat suspect anyhow. I mean, the wild animals dont give a hoot if their breeding partner is "100% pure" anything. Mr happy ambilobe isnt concerned to know if the great grandfather of that nice little female ambilobe over there was 25% sambava. Heck he doesnt care if she's 100%sambava. The animals move about, local people in Madagascar have likely moved some about, importers guess or rely on local collectors who dont care or know that it matters, some importers just tell buyers what they want to hear. And if you see the pictures of some chameleons in various locations of Madagascar, they often look quite different from what North Americans seem to think they should look like.
Sorry, my two cents seems to have turned into $1.50! LOL but still not worth much. LOL