I have seen some weird examples of people who have a basically normal animal but so badly want it to BE SOMETHING that they convince themselves of something blatantly wrong. They make themselves look very bad, but at least it's obvious to most people that the picture is not of an enchi or a black pastel.
The hets thing, I think that's usually done with intent to deceive. Especially with possible hets you have to be careful, because so what if the animal NEVER proves? It was only a POSSIBILITY, after all! (...she says, even though she is selling a bunch of them. But the husband wants them out of the house! And I haven't got the heart to wholesale my very first clutch... Sigh.)