A 2012 report from the U.S. Surgeon General stated: "Another common practice is strategically locating tobacco-related marketing materials where young children will be exposed to them. Tobacco industry executives acknowledge that products and advertising should be placed at eye level (Pollay 2007), but in California, 48% of stores had at least one cigarette marketing item at or below 3 feet from the floor (Feighery et al. 2001)." It was also noted that 25% of cigarette displays were next to candy. In addition, a national study found that about one-third of the stores had tobacco ads at low heights. After California banned counter displays, some stores place cigarettes in a see-through display so product brands could still be seen. What is the main reason that states like California ban counter displays of tobacco products?