I used to work at a government lottery and often worked with the Integrity and Compliance people. One day the Compliance guy told me the balls they used for on

I used to work at a government lottery and often worked with the Integrity and Compliance people. One day the Compliance guy told me the balls they used for one of the draws are stored in a vault, no surprise. But he also said they wash and weigh the balls before each use. Actual physical bouncy balls of some sort.