I have no idea what percentage of readers have ever experienced random drug testing, particularly in its more humiliating forms. Having served for ten years in the Navy, I can speak from experience, having been subjected to at least 15 (passed without studying...)...
Who speaks from a legal standard for the testing? Also, testing mistakes do occur (false positives), aside from clerical errors, or administrative errors (samples mixed up). The system isn't foolproof, although generally of high quality.
Congress has taken it upon themselves to demand testing. Were I Donald Fehr (a scary thought) I wouldn't be able to say what he must really think, "Our union supports drug-free professional sports and remains committed to the highest standards of quality and ethics in society. Nothing is more important than the preservation of liberty and clarity of thought among our elected officials. We agree to a two-year ban for a positive test, and lifetime ban for two positives...providing the Congress, the Cabinet, and the President and the Vice President of the United States and their staff agree to the same policy and consequences, i.e. random testing under direct observation."
That will never happen.