maf

I posted a while back about how I have only smoked once in my life and it was 1-2 hits a month ago and I am still paranoid about my upcoming hair test. Anyway, I was just wondering why they prefer to remove hair from people's heads? I generally keep my hair very short, so if I get a buzzcut right before my test to like 1/2in would they take hair from my arm pit? Would that be less likely to turn out positive? Or can I tell them that I do not care if they take it from my head eventhough it will leave a bald spot?