[a0zU]

Coding challanges are used pretty often to scam programmers to do work for free before the company rejects them.

[twic]

I don't believe this actually happens. Do you have any concrete examples?

[mamon]

There's this infamous company from Austin, Texas, which hires programmers for remote work, and they typically give you coding "challenges" that require a week to complete, and are complete (although not very complex) applications.