They want to make really sure you don't try to cheat on the urine tests. They take a lot of precautions. 1. The water in the toilet is blue, so you can't get away with adding it to the sample, 2. The back of the toilet tank is chained shut, 3. You have to lock your purse in a little box before going into the bathroom to give your sample, and 4. The urine collection container has a thermometer strip on it to make sure it just came out of your body. Of course, I DO know of ways to get around all of that, but I'm clean so I have no reason to want to cheat. For example, they sell these "shooter" things in bars in a tube... I've heard of people having a clean friend pee in one of those to take and substitute... but I suppose you'd have to stick it in your vagina like a tampon to get it to be the right temperature... and I don't know WHAT a guy would do... plus you have to fill the cup to a certain level, and I don't know if one of those shooters would hold enough liquid. There are also the drinks that clean your pee, and I know people who have successfully passed drug tests while indulging in drug use by using those, so I know they work, but I also know others for whom they did NOT work. I think if you follow the instructions properly they work, and they have a money back guarantee...