Line breeding or not, if there are 'markers' then it is phenotypically different than a wild type. Just because only 10 out of 100 people can identify the hets does not mean that the other 90 must be right. It just means the 90 are not as trained at picking out the gene. Heck how often do you see people on this forum asking if their normal is a yellow belly or if their yellow belly really is one? Does that make it recessive? Some people cant see subtle differences, or they are not as trained to do so, even if those subtle differences are not so subtle.