heres the problem: Common detection times: Alcohol (Beer, Booze, Hooch, Liquor, Wine), 1 hour to perhaps 10 or 12 hours Amphetamines (Biphetamine, Black Beauties, Crosses, Dexedrine, Hearts), 1-2 days Barbituates (Amytal, Nembutal, Seconal, Phenobarbital; Barbs), 2-3 days Benzodiazepines (e.g., Ativan, Halcion, Librium, Rohypnol, Valium; Roofies, Tranks, Xanax), 2-3 days Cocaine (Candy, Coke, Crack, Flake, Rocks, Snow, Whitecoat), 1-2 days Codeine (e.g., Fiorinal w/codeine, Robitussin A-C, Empirin w/codeine, Tylenol w/codeine, 1-2 days GHB (G, Grievous Bodily Harm, Goob, Liquid Ecstasy, Liquid X), 1-2 days Heroin (Horse, Smack), 1-2 days Inhalants, just a few hours Ketamine (K, Kit Kat, Special K, Vitamin K), 2-4 days LSD (Acid, Blotter, Microdot, Yellow sunshine), a few hours or up to 5 days Marijuana (Bud, Blunt, Grass, Herb, Pot, Reefer, Sinsemilla, Smoke, Weed), 10-15 days (the daily, heavy user can sometimes be detected up to 30+ days) MDMA (Ecstasy), 1-5 days Methadone, 1-7 days Methamphetamines (Crank, Crystal, Desoxyn, Glass, Ice, Speed), 2-4 days Methaqualone (Ludes, Quaaludes), 10-15 days Nicotine (Cigarettes, Cigars, Habitrol patch, Nicorette gum, Nicotrol spray, Prostep patch; Smokeless tobacco, Snuff, Spit tobacco), 1-2 days Opiates (i.e., Opium: China, Dreams, Laudanum, Paregoric; Dover's Powder), 1-2 days Oxycodone (OxyContin, Percolone, Roxicodone), 1-2 days PCP (Angel Dust, Boat, Hog, Love Boat), 1-8 days Coke is an easy problem to hide, its just in your system for 1-2 days. So unless you are testing the person daily, you will have no idea. The problem with drug tests are the only thing they find is weed cause it stays in your system longer then anything else. All your doing is encouraging people to stop smoking weed and move onto harder stuff that is harder to detect.