Wouldn't it be interesting if everyone participating in these types of interview challenges refused to do them unless the work could be turned into a reference

Wouldn't it be interesting if everyone participating in these types of interview challenges refused to do them unless the work could be turned into a reference piece like this guy did? I doubt many companies would like that, but if a majority of people refused to participate without that clause, who knows? Clearly several people in this thread felt like they were being asked to do work which would be put into production and this would prevent that (though I personally am REALLY skeptical of those stories). It seems crazy that people are being asked to do work for even a few hours for "free" much less several days of work. If you are doing that, it seems totally fair to indicate that this work will be made public afterwards and made into a portfolio piece.