One of the worst examples was the very deliberate placement of aeration holes in cigarette filters where they knew that smokers typically cover with their fingers (Anderson, Ling, & Pollay, 2006). They had discovered the perfect placement where the holes reduced tar and nicotine levels when the cigarettes were inserted in the laboratory equipment used to test-smoke cigarettes but where they were covered up by smokers' fingers. They purposely marketed "low-tar" and "low-yield" cigarettes based on the lab tests knowing that tests of smokers indicated they would be put off by the reduced satisfaction of cigarettes that were, in fact, lower yield (Anderson, Ling, & Pollay, 2006) with the use of Aristotle's logos rhetoric through the logic of the informational argument that lower-yield tobacco products were obviously less dangerous to human health.

The first phase of tobacco product advertising was no different, ethically, than the common advertising of consumer goods...

However, since the tobacco companies became aware that their products are tremendously dangerous to human health, they have had an ethical duty to comply with formal restrictions in good faith. Their record has been diametrically opposite, unfortunately.
Sources Consulted

Anderson, S., Ling, P., and Pollay, R. "Taking Ad-vantage of Consumers: Advertising

Light Cigarettes: Reassuring and Distracting Concerned Smokers"

Social Science & Medicine, 2006, Vol. 63, No. 8: 1973-1985.

Cummings, K., Pollay, R. (2002). "Exposing Mr. Butts: Tricks of the Trade:

Discoveries and Disclosures in the Tobacco Documents" Tobacco Control

(Special Issue), Vol. 11, Supplement No.1: i1-i4.

Pollay, R. (2007). "History of Cigarette Advertising," in Jeffrey Jensen Arnett (Ed.),

Encyclopedia of Children, Adolescents, and the Media. Thousand Oaks, CA:

Sage Publications.