But such policies seem instead to have created the conditions for even more campus violence. Some college students who previously drank in bars and lounges under the watchful supervision of bouncers(夜总会,就把等保安人员)(not to mention owners eager to keep their liquor licenses) now retreat to the sanctuary of their fraternity houses and apartments, where they no longer control their behavior their drinking. The boomerang effect has also played a role in attempts to reduce the availability of illicit drugs. During recent years, the federal government has been quite successful in reducing the supply of street drugs. As fields are burned and contraband(违禁品) confiscated, the price of street drugs has skyrocketed to a point where cheap alternatives have begun to compete in the marketplace. Unfortunately, the cheap alternatives are even more harmful than the illicit drugs they replace.