I grew a small, but very potent crop of marijuana while stationed in Bremerton, WA while my ship was in the shipyard. At some point around mid-summer of that crop growing summer I was late for work. At that point in Navy random urinalysis testing if you were late for work you were asked to sign a form stating that you were voluntarily submitting to a urinalysis so that the Navy could use the results as evidence in non-judicial punishment. I decided I'd rather not sign that form, and I was harassed and badgered for a full day before I was finally sent to the shipyard base hospital and finally ordered to pee in the bottle even though I wouldn't sign the form. I then followed the order and was sent back to my ship and went home at the end of the work day.
I was pretty good friends with th one of the radio-men, and it was the radio-men who received the results of this urinalysis. They didn't tell me until much later that this result and one other they made disappear came back incendiary hot. But for the rest of that summer my number or letter (last digit of SSN or first letter of last name) was called about weekly or so. The rest of the non-chief enlisted guys in engineering department knew the whole story, because I was giving them weed on a regular basis. Every time I came up to bat I used the old feed and bleed. Chug water all day until your piss is so clear it's nearly gaseous, then fill the bottle at the end of the day. I was fairly certain I was going to get busted on one of these "random" piss tests, but I never did. The one the radio-men covered for me on happened after we got out of the shipyard.
I was so convinced I was going to get caught that I sent a letter to the Seattle music newspaper explaining the situation and asking if I could write for them when I got kicked out of the Navy. But it never came to pass. All that happened was the Navy changed their policy on late to work piss tests.