i do love this idea but not sure if doing it remotely is a good idea. We do this in house because I am not sure how to be certain the candidate did not get help. I mean i believe people are generally honest but there will be cases when they are not, and I'd rather not find out 3 months after hiring them.

Also there are many indicators along the way, i.e. which parts the candidate got stuck at, did it take them 1 or 3 hrs to get to the same point (i.e. basic wiring of DB calls). I think all that would be lost if they did it on their own time.