Saying "1% bodyfat" doesn't really mean much, because even the most accurate methods of measuring bodyfat have a not insignificant margin of error. And skin-fold calipers, the most common way (in my experience) of measuring bodyfat, definitely have a significant margin of error.

You might actually read 1% on the skinfold caliper, but that doesn't necessarily mean you literally have only 1% bodyfat.

http://en.wikipedia.org/wiki/Body_fat_percentage