What is the difference between a contracted 18 day cut off and random testing where 18 days was the last test?

Man this is like trying to pound a square into a circle with some of these guys. Without using a thousand charecters attempting to justify nonsense, how are these options different? What is the difference between having an 18 day cut off written in your contract, and a commision with their presence looming over you 24 hours a day deciding not to test within that time frame? People keep arguing the effectiveness of testing, blah blah, that doesn't negate the FACT that the comission could have tested either up to the date which makes a contracted cutoff date not as effective as random up to date.. do you get it yet?