I assume a working with children check wouldn't have a high standard of evidence and a candidate probably doesn't need a conviction to fail the test. E.g., it would be enough for a previous employer to say "Oh yeah we couldn't prove it but we had some serious complaints that he was fiddling kids". If that is the case, I really don't feel comfortable with this direction. If its more of a case where theres some established quantifiable criteria that would never reasonably pass appeal, then sure... but I don't get what this solves except to save resources.
It strikes me as opportunistic politics to appeal to the emotion of voters--which is just tacky when we are talking about something as serious as peoples careers and child safety.