Actually 99% of the time that IS the case which is why I don't really like places like the BOI. Places like that tend to make it sound like half the people in this hobby are criminals and that's just NOT the case.
As for Mojaves VS Mystics, the Mystics are darker. I remember speaking to the guy who discovered the Mystics when he first started producing them. He wasn't sure himself what he had when he imported that first animal. He couldn't make up his mind if it was a new gene or just a particularly dark Mojave. It wasn't until he had produced several clutches of them that he knew for sure that he had something different. The same thing happend with Ralph Davis when he started producing his Phantoms, he thought it was an ugly Mojave, but it turned out to be something different. I think most people now believe that Phantoms and Mystics are exactly the same thing, just different lines of the same mutation.
I'm not sure about the 'green hue' in Mojaves It's not really green but I can see where people would explain it like that. They do have a different look to them then the mystics but it's kind of hard to describe.