Is Ethics Needed in Business?

Saw this question on some website the other day. Interesting question, since one would think the answer would be obvious. Yes, of course we need ethics in the workplace. After scandals of Enron, WorldCom, Madoff, etc., it would not only be needed, but mandated. Yet, you are dealing with the human element that can have differences on what "ethics is".
I see it more of leading by example. If you want to create a policy in the workplace, don't counter what you want by doing the opposite. If, you wish to promote a good health in your office (for the benefit of the employees themselves and save on you health plan costs), don't counter that argument by leaders going around and smoking in the parking lot. If you wish to promote a healthy lifestyle, should executives promote a culture of drinking at company events, or have have severe weight issues themselves? Leaders will be followed if the employees believe their efforts are sincere. Do as I say, not as I do, can not be the mantra of the work space.
Promote positive work culture via examples of the executives. They must lead (is that why they were elevated to these positions?). Encourage by setting the pace, and if further, provide monetary incentives to employees to promote a healthy lifestyle. Make sure you set the tone.