Going too far?

A company in Michigan has now banned its employees from smoking, even off hours.
Article.

I myself am not a smoker, but it just seems like this is pushing a fine line. Where does it end? How much control can/should an employer have over an employee's personal lifestyle? You could argue that, since the company is (I'm assuming) helping fund employee's health insurance costs, the employer should be able to exercise some influence on how those costs are utilized. In other words, if I have to help pay for your health insurance, I should have a say in your health. But again, that starts to fall into some grey areas. What are the threshholds of tolerance? Are companies going to start publishing an accepted weight level based on height, gender, etc? Is there also going to be an established acceptable level of blood pressure, resting heart rate, cholesterol? It may lead to a healthier society but is this really way the means to control it? Be healthy or you're fired... I'm sure the pharmaceutical companies would love this. People would be popping pills left and right.

Did anyone watch Gattaca?