I drank - but never drank vodka specifically to avoid detection. If I drank vodka or gin, it'd usually be as a tonic - and at the back of my mind, an additional reason might include the fact that they were lower in
congeners than spirits like whiskey and rum (which I also drank).
It's interesting how powerful certain myths can be - in particular, the one that vodka can't be detected on one's breath. The Smirnoff vodka "leaves you breathless' ad was concocted almost 60 years ago in 1952. Even when I was drinking, I recall running into alcoholics who drank vodka during the day. The Dean of my grad school was oh-so certain no one knew about his afternoon vodka habit but the fumes were so heavy I could have lit them with a lighter and used him as a flamethrower.