Biting is less of an issue than the possibility that they will poop all over you - less of a mess with boids than colubrids, but either way it tends to be abundant, wet and stinky! even from a very small snake.
When we do demonstrations with the local club, kids are always wanting to let snakes crawl all over them, around their neck and in their hair. Not something we allow - too much risk of a snake being either too stressed or too comfortable and letting loose!
We confine snakes, especially colubrids, to our hands and arms - being pooped on once (and that was over my arm and sleeve) was enough for me - NEVER want that to happen again.