Clean zones raise a bevy of concerns.

For one, clean zones unabashedly limit competition when businesses are denied permission from the league or city. A decrease in competition implicates two core worries of antitrust law: fewer choices and higher prices for consumers. So perhaps instead of two dozen T-shirt street vendors around Lucas Oil Stadium, the NFL only grants permission to a handful. Although they would still compete with vendors of other items, the licensed vendors might charge more and offer less variety.

Second, clean zones restrict commercial speech, meaning speech that solicits a commercial transaction, such as when a company advertises or promotes a product. To be sure, commercial speech is accorded much less protection under the law than political speech. While the First Amendment aggressively protects one's right to express personal opinions from government suppression, a government, such as the City of Indianapolis, can readily limit commercial speech that is deceptive and misleading.

Eric Williams v. NFL: A Clean Zone Test Case

Last year anti-bullying advocate Eric Williams teamed up with Best Buy on what seemed like a promising idea: Williams would park his bus in Best Buy's parking lot near Cowboys Stadium between Feb. 4 and Feb. 6 and host a John Madden video game tournament. Williams would charge participants of the tournament, which would teach children about how to detect and stop bullying.

The tournament never happened.

Arlington police and code enforcement officers asked Williams if he had a permit to be there. He did not and saw no reason why he should. After all, his bus was on Best Buy's private property, with the store's express invitation. The security officers nonetheless insisted that Williams move the bus, since it was a commercial operation located within a clean zone ordinance.