False advertising harms consumers and is damaging to a fair marketplace. It is also illegal.
Under the Federal Trade Commission Act:
In addition to false advertising being a violation of Federal law, all 50 states have legislation aimed at protecting consumers in their state from deceptive practices. 19 states have adopted the Uniform Deceptive Trade Practices Act [3] while the remaining states have their own, similar laws. The consumer protection laws in 49 states explicitly forbid false advertising. [4]