I second what Joanna said. I am very confident that my three hets are exactly that and not just normals. Two came from Adam Wysocki (the het pied and het hypo) and one came from Justin Kobylka (the het clown). The reason I am confident is because both gentlemen have stellar reputations in the community and were checked out thoroughly before purchasing from them.
You MUST trust your breeder when buying hets. Hets are an awesome way to get into recessives if you can't afford the visible morph!