One particularly persistent group of legends is that of treasures in caves. We have already discussed the typical legend of a treasure in a cave. Just think of the spectacular scene from Treasure of the Silver Lake (for older readers) or Pirates of the Caribbean. For literature lovers, perhaps The Count of Monte Cristo. None of these are historical facts, but rather a meme that has become established in our culture, completely independent of its truthfulness.
When you are planning a scam by selling faked artifacts of any kind, you need a good explanation where you found them. Probably the simplest and therefore most plausible explanation is treasure in a cave. Although it is highly unlikely that anything of value would be stored in a damp cave, we have seen it so often in films and read about it so often in books that we simply believe it.