A commonly used technique to avoid gambling laws in a number of states was to award food prizes. For this reason, a number of gumball and other vending machines were regarded with mistrust by the courts. The two Iowa cases of "State v. Ellis" and "State v. Striggles" are both used in criminal law classes to illustrate the concept of reliance upon authority as it relates to the axiomatic "ignorantia juris non excusat" ("ignorance of the law is no excuse"). In these cases, a mint vending machine was declared to be a gambling device because the machine would, by internally manufactured chance, occasionally give the next user a number of tokens exchangeable for more candy. Despite the display of the result of the next use on the machine, the courts ruled that "machine appealed to the player's propensity to gamble, and that is [a vice."