What may be difficult to quantify, is that an ethical consultant, more often than not, benefits the company by keeping legal expenses down by guiding the company down a safe path. The end result is the company does not find itself it hot water thru either criminal or civil proceedings.
This ends up, not really "saving" the company money, but prevents the company from having to spend earned profit on legal costs, civil suits, and the like. So the profit numbers remain high, and the owner(s) get a good return on investment.
What IMHO is a shame, is that proper oversight, either internal or external, is necessary to prevent malfeasance on the part of management. Human nature is what it is, and as much as we'd all agree that ethics is a life-style (see thread by rbeaureg), most human beings do not practice that way of life. Thus the need for the ethical consultant.
The cost does get passed on to the consumer, but how much are willing to pay not to get screwed, or not to see your neighbor get screwed? Good Luck
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As a circle of light increases so does the circumference of darkness around it. - Albert Einstein