LEV402 Even in today's non-Jewish world, there is a concept of immoral advertising. The classic example of this is "bait and switch," where a product is advertised at a ridiculously low price in order to get people into the store. When they arrive, this salesperson indicates that the sale products have been sold out and then proceeds to sell the customer another similar, more expensive product. The immorality of this practice is patent because the owner never really meant to sell the original product and usually will have just a few, if any, available in the first place. This ruse actually lures many people to the store and some do buy other products at higher prices (which they never would have purchased had they not been lured into the store). From a Jewish perspective, the reason this scheme is immoral and illegal involves the violation of several principles. The verse in Leviticus (19:36) commands a Jew to have just and accurate weights and measures. Playing on the word "hin" in the verse, which is an amount, the Talmud (Bava Metzia 49a) says that your "hen", your "yes," should be just and truthful. This implies that if you promise something, you're not permitted to intentionally violate that promise. Thus, misleading through "bait and switch" is clearly forbidden. In addition, according to some commentaries, this type of action clearly violates the prohibition of "putting a stumbling block in front of a blind person" [this verse], which also forbids misleading a prison intentionally. Hence, any type of advertising that intentionally misleads people seems to be forbidden. This general concept, which most clearly defines whether advertising is legitimate or not, is called geneivat daat. Technically translated as "stealing a person's thought," this idea suggests that intentionally misleading a person or misrepresenting the truth is a clear violation of proper Jewish practice.