Be VERY, VERY careful with subbing for probation test. Most probation officers EXPECT people to try to cheat and therefore take extra precautions to make sure you don't use artificial items. I don't know about probation test, but there is a new law which went into effect November 1st 2008 for DOT observed test. If you have to do an observed test the person being tested has to drop trousers and/or undies to the knees and make one complete turn in front of tester.