Exactly why without NCAA rules and enforcement on who, when and what happens the testing process is wide open to fraud and cheating.
I am sure all of us have a list of coaches that we would not trust to do the right thing.
Testing is for a potentially lethal virus and is done not only for you but your team mates, the coaches, the trainers etc.
Most rational employers and coaches realize their employees and players are their most valuable assets and do not want a mini epidemic in the workplace or locker room.