I'm going to use Ed for black gene, e for the red, and E+ for wild type (comes from http://homepage.usask.ca/~schmutz/colors.html where they talk about it, and where I'm basing this discussion off of).
If EdE+ animals come out black, then crossing E+E+ animals to each other shouldn't result in true black, as there are no black genes left. However, I do like your analogy that it might be like going to Vegas. Yes some of these E+E+ animals might look very close to regular red, but some....don't. Now just my own personal theory, it's possible they could luck out and Angus/Lowline don't have any or many modifiers that can act on top of wild type (eg. Jersey type shading, brindling, and whatever ones we don't even know about) so they might get less crazy colors and get away with it. But if it were me I would probably be trying for real red genes eventually, rather than "faking" it (because if you can get them red, they will breed true...handy). The advantage I can see for them though, is in the process, they definitely might have an easier time promoting eE+ animals that ARE red for "Redlines", than they would a Ede animal that is black (yet each still has one copy of the red gene).
