We have a filing cabinet in our testing room secured with Velcro so our donors have a safe place to put their belongings but are not able to tamper with their sample.
Recently, a woman came in to test for her employer. After she entered the restroom, the collector heard her urinating and everything sounded normal. However, she remained in the bathroom for a long time, much longer than was necessary. When she emerged, the urine she presented to the collector was bright yellow, similar in color to Mellow Yellow. All other indicators that we check, other than the color, were correct.