Nah, not concerned at all. I'm just pointing out that auditions like this necessarily rule out a large subset of the population right off the bat. Maybe that's okay for your business objectives, maybe it's not. Maybe you're looking for "the best" and not qualifying "the best what." Maybe you're ruling out the best senior developers (who may not have time for this or have little to prove) and picking up the best junior developers (who may have spare time and everything to prove). Maybe that's acceptable to you. Or maybe that's exactly what you want.
I'm not saying "don't do it." I'm saying that from my perspective, I think it's a flawed interviewing technique and it's not something I would be interested in when applying for a job.
If it works for you, then by all means go for it. I'm just saying it doesn't work for me.