That filters for people who have three days to spend on a coding challenge with no guarantees at all. If you're unemployed, straight out of school, or very diss

That filters for people who have three days to spend on a coding challenge with no guarantees at all. If you're unemployed, straight out of school, or very dissatisfied at your current job (perhaps due to conflicts), you're much more likely to take such a challenge than if you have a lot of experience but a full time job and a family. You might not mind that filter (hiring cheaper but talented young people), but it's surely a bias.