When you use practices like this, you encourage payors or regulators to tell you what to do. You remove physician judgment, which means that they can substitute their own judgment. So, not only is it unethical, it's not smart practice.
I just reviewed an outside case from a physician owned lab of a 12 core prostate biopsy, with cancer in 9 of 12 cores (some cores 100% involved). Outside path did a triple cocktail on 8 separate blocks. This infuriates me because it is the kind of practice that draws attention to pathology as a source for overspending and overutilization. Sadly, a lot of doctors think this is OK for various reasons (like they're not getting adequately paid for something else they are required to do, so they charge other stuff so they get paid for that instead). This is exactly the way to get replaced, because your judgment is less relevant to your practice.